From 0eef7f0e1102ff9fcd6e81c1d081648b0946ef47 Mon Sep 17 00:00:00 2001
From: Sjors Provoost <sjors@sprovoost.nl>
Date: Tue, 12 May 2026 10:02:36 +0200
Subject: [PATCH 1/2] build: move library sources under lib/ for subtree split

Move the library sources (CMakeLists.txt, cmake/, include/, pkgconfig/,
src/, test/) under a single lib/ prefix so that

    git subtree split --prefix=lib -b lib

produces a 'lib' branch containing only the files needed for a full
library build and install. Downstream projects consuming libmultiprocess
as a git subtree can pull from this branch and avoid churn from changes
to CI scripts, README, doc/, examples, shell.nix and other files that
are not part of the library itself.

A new top-level CMakeLists.txt wrapper preserves 'cmake -S .' for
standalone builds; this is also the only way to build the example/
subdirectory, which lives outside lib/ since downstream subtree
consumers do not need it. See comments in CMakeLists.txt and
lib/CMakeLists.txt for details on how lib/ adapts between the two
build modes.

The bulk of this commit is a pure file move (renames only). Outside
the move itself, only minimal touch-ups were necessary in
lib/CMakeLists.txt and ci/scripts/{ci,bitcoin_core_ci}.sh.
---
 CMakeLists.txt                                | 269 ++---------------
 ci/scripts/bitcoin_core_ci.sh                 |   6 +-
 ci/scripts/ci.sh                              |   6 +
 example/CMakeLists.txt                        |   2 -
 lib/CMakeLists.txt                            | 276 ++++++++++++++++++
 {cmake => lib/cmake}/Config.cmake.in          |   0
 {cmake => lib/cmake}/TargetCapnpSources.cmake |   0
 {cmake => lib/cmake}/compat_config.cmake      |   0
 {cmake => lib/cmake}/compat_find.cmake        |   0
 {cmake => lib/cmake}/pthread_checks.cmake     |   0
 {include => lib/include}/mp/config.h.in       |   0
 {include => lib/include}/mp/proxy-io.h        |   0
 {include => lib/include}/mp/proxy-types.h     |   0
 {include => lib/include}/mp/proxy.capnp       |   0
 {include => lib/include}/mp/proxy.h           |   0
 {include => lib/include}/mp/type-char.h       |   0
 {include => lib/include}/mp/type-chrono.h     |   0
 {include => lib/include}/mp/type-context.h    |   0
 {include => lib/include}/mp/type-data.h       |   0
 {include => lib/include}/mp/type-decay.h      |   0
 {include => lib/include}/mp/type-exception.h  |   0
 {include => lib/include}/mp/type-function.h   |   0
 {include => lib/include}/mp/type-interface.h  |   0
 {include => lib/include}/mp/type-map.h        |   0
 {include => lib/include}/mp/type-message.h    |   0
 {include => lib/include}/mp/type-number.h     |   0
 {include => lib/include}/mp/type-optional.h   |   0
 {include => lib/include}/mp/type-pair.h       |   0
 {include => lib/include}/mp/type-pointer.h    |   0
 {include => lib/include}/mp/type-set.h        |   0
 {include => lib/include}/mp/type-string.h     |   0
 {include => lib/include}/mp/type-struct.h     |   0
 {include => lib/include}/mp/type-threadmap.h  |   0
 {include => lib/include}/mp/type-tuple.h      |   0
 {include => lib/include}/mp/type-vector.h     |   0
 {include => lib/include}/mp/type-void.h       |   0
 {include => lib/include}/mp/util.h            |   0
 {include => lib/include}/mp/version.h         |   0
 {include => lib/include}/mpgen.mk             |   0
 .../pkgconfig}/libmultiprocess.pc.in          |   0
 {src => lib/src}/mp/gen.cpp                   |   0
 {src => lib/src}/mp/proxy.cpp                 |   0
 {src => lib/src}/mp/util.cpp                  |   0
 {test => lib/test}/CMakeLists.txt             |   2 +-
 {test => lib/test}/mp/test/foo-types.h        |   0
 {test => lib/test}/mp/test/foo.capnp          |   0
 {test => lib/test}/mp/test/foo.h              |   0
 {test => lib/test}/mp/test/spawn_tests.cpp    |   0
 {test => lib/test}/mp/test/test.cpp           |   0
 49 files changed, 305 insertions(+), 256 deletions(-)
 create mode 100644 lib/CMakeLists.txt
 rename {cmake => lib/cmake}/Config.cmake.in (100%)
 rename {cmake => lib/cmake}/TargetCapnpSources.cmake (100%)
 rename {cmake => lib/cmake}/compat_config.cmake (100%)
 rename {cmake => lib/cmake}/compat_find.cmake (100%)
 rename {cmake => lib/cmake}/pthread_checks.cmake (100%)
 rename {include => lib/include}/mp/config.h.in (100%)
 rename {include => lib/include}/mp/proxy-io.h (100%)
 rename {include => lib/include}/mp/proxy-types.h (100%)
 rename {include => lib/include}/mp/proxy.capnp (100%)
 rename {include => lib/include}/mp/proxy.h (100%)
 rename {include => lib/include}/mp/type-char.h (100%)
 rename {include => lib/include}/mp/type-chrono.h (100%)
 rename {include => lib/include}/mp/type-context.h (100%)
 rename {include => lib/include}/mp/type-data.h (100%)
 rename {include => lib/include}/mp/type-decay.h (100%)
 rename {include => lib/include}/mp/type-exception.h (100%)
 rename {include => lib/include}/mp/type-function.h (100%)
 rename {include => lib/include}/mp/type-interface.h (100%)
 rename {include => lib/include}/mp/type-map.h (100%)
 rename {include => lib/include}/mp/type-message.h (100%)
 rename {include => lib/include}/mp/type-number.h (100%)
 rename {include => lib/include}/mp/type-optional.h (100%)
 rename {include => lib/include}/mp/type-pair.h (100%)
 rename {include => lib/include}/mp/type-pointer.h (100%)
 rename {include => lib/include}/mp/type-set.h (100%)
 rename {include => lib/include}/mp/type-string.h (100%)
 rename {include => lib/include}/mp/type-struct.h (100%)
 rename {include => lib/include}/mp/type-threadmap.h (100%)
 rename {include => lib/include}/mp/type-tuple.h (100%)
 rename {include => lib/include}/mp/type-vector.h (100%)
 rename {include => lib/include}/mp/type-void.h (100%)
 rename {include => lib/include}/mp/util.h (100%)
 rename {include => lib/include}/mp/version.h (100%)
 rename {include => lib/include}/mpgen.mk (100%)
 rename {pkgconfig => lib/pkgconfig}/libmultiprocess.pc.in (100%)
 rename {src => lib/src}/mp/gen.cpp (100%)
 rename {src => lib/src}/mp/proxy.cpp (100%)
 rename {src => lib/src}/mp/util.cpp (100%)
 rename {test => lib/test}/CMakeLists.txt (96%)
 rename {test => lib/test}/mp/test/foo-types.h (100%)
 rename {test => lib/test}/mp/test/foo.capnp (100%)
 rename {test => lib/test}/mp/test/foo.h (100%)
 rename {test => lib/test}/mp/test/spawn_tests.cpp (100%)
 rename {test => lib/test}/mp/test/test.cpp (100%)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a36023b1..b36daffe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,263 +2,30 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+# Top-level wrapper for standalone builds (`cmake -S .`). Adds the example
+# subdirectory, which is the only thing not relevant to subtree consumers
+# (which configure `lib/` directly via `add_subdirectory()`).
+#
+# The actual library, generator, headers, tests and pkg-config template live
+# under `lib/` so that `git subtree split --prefix=lib` produces a `lib`
+# branch suitable for use as a slim git subtree by downstream projects.
+
 cmake_minimum_required(VERSION 3.12)
 
 project("Libmultiprocess" CXX)
-if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  set(CMAKE_CXX_STANDARD 20)
-  set(CMAKE_CXX_STANDARD_REQUIRED YES)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 
-include("cmake/compat_find.cmake")
+# Tell lib/CMakeLists.txt that this is a standalone build, even though it is
+# being processed via add_subdirectory() rather than as the top-level source.
+set(MP_STANDALONE TRUE)
+include(CTest)
 
+# Threads::Threads and Cap'n Proto targets are needed by the example/
+# subdirectory. find_package() creates IMPORTED targets in the calling
+# directory's scope, so do it here as well as in lib/CMakeLists.txt.
 find_package(Threads REQUIRED)
 find_package(CapnProto 0.7 QUIET NO_MODULE)
- if(NOT CapnProto_FOUND)
-   message(FATAL_ERROR
-     "Cap'n Proto is required but was not found.\n"
-     "To resolve, choose one of the following:\n"
-     "  - Install Cap'n Proto (version 1.0+ recommended)\n"
-     "  - For Bitcoin Core compilation build with -DENABLE_IPC=OFF to disable multiprocess support\n"
-   )
- endif()
-
-# Cap'n Proto compatibility checks
-set(CAPNPROTO_ISSUES "")
-set(CAPNPROTO_CVE_AFFECTED FALSE)
-set(CAPNPROTO_CLANG_INCOMPATIBLE FALSE)
-
-# Check for list-of-pointers memory access bug from Nov 2022
-# https://nvd.nist.gov/vuln/detail/CVE-2022-46149
-# https://github.com/advisories/GHSA-qqff-4vw4-f6hx
-# https://github.com/capnproto/capnproto/security/advisories/GHSA-qqff-4vw4-f6hx
-# https://github.com/capnproto/capnproto/blob/master/security-advisories/2022-11-30-0-pointer-list-bounds.md
-# https://capnproto.org/news/2022-11-30-CVE-2022-46149-security-advisory.html
-# https://dwrensha.github.io/capnproto-rust/2022/11/30/out_of_bounds_memory_access_bug.html
-if(CapnProto_VERSION STREQUAL "0.7.0"
-   OR CapnProto_VERSION STREQUAL "0.8.0"
-   OR CapnProto_VERSION STREQUAL "0.9.0"
-   OR CapnProto_VERSION STREQUAL "0.9.1"
-   OR CapnProto_VERSION STREQUAL "0.10.0"
-   OR CapnProto_VERSION STREQUAL "0.10.1"
-   OR CapnProto_VERSION STREQUAL "0.10.2")
-  set(CAPNPROTO_CVE_AFFECTED TRUE)
-  string(APPEND CAPNPROTO_ISSUES "- CVE-2022-46149 security vulnerability (details: https://github.com/advisories/GHSA-qqff-4vw4-f6hx)\n")
-endif()
-
-# Check for Cap'n Proto / Clang / C++20 incompatibility
-# Cap'n Proto 0.9.x and 0.10.x are incompatible with Clang 16+ when using C++20
-# due to P2468R2 implementation. This was fixed in Cap'n Proto 1.0+.
-# See: https://github.com/bitcoin-core/libmultiprocess/issues/199
-if((CapnProto_VERSION VERSION_GREATER_EQUAL "0.9.0") AND
-   (CapnProto_VERSION VERSION_LESS "1.0.0") AND
-   (CMAKE_CXX_COMPILER_ID STREQUAL "Clang") AND
-   (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "16") AND
-   (CMAKE_CXX_STANDARD EQUAL 20))
-  set(CAPNPROTO_CLANG_INCOMPATIBLE TRUE)
-  string(APPEND CAPNPROTO_ISSUES "- Incompatible with Clang ${CMAKE_CXX_COMPILER_VERSION} when using C++20\n")
-endif()
-
-if(CAPNPROTO_CVE_AFFECTED OR CAPNPROTO_CLANG_INCOMPATIBLE)
-  set(RESOLUTION_OPTIONS "")
-
-  # Fixes both issues
-  string(APPEND RESOLUTION_OPTIONS "  - Upgrade to Cap'n Proto version 1.0 or newer (recommended)\n")
-
-  if(CAPNPROTO_CVE_AFFECTED AND NOT CAPNPROTO_CLANG_INCOMPATIBLE)
-    string(APPEND RESOLUTION_OPTIONS "  - Upgrade to a patched minor version (0.7.1, 0.8.1, 0.9.2, 0.10.3, or later)\n")
-  elseif(CAPNPROTO_CLANG_INCOMPATIBLE AND NOT CAPNPROTO_CVE_AFFECTED)
-    string(APPEND RESOLUTION_OPTIONS "  - Use GCC instead of Clang\n")
-  endif()
-
-  string(APPEND RESOLUTION_OPTIONS "  - For Bitcoin Core compilation build with -DENABLE_IPC=OFF to disable multiprocess support\n")
-
-  message(FATAL_ERROR
-    "The version of Cap'n Proto detected: ${CapnProto_VERSION} has known compatibility issues:\n"
-    "${CAPNPROTO_ISSUES}"
-    "To resolve, choose one of the following:\n"
-    "${RESOLUTION_OPTIONS}"
-  )
-endif()
-
-set(MPGEN_EXECUTABLE "" CACHE FILEPATH "If specified, should be full path to an external mpgen binary to use rather than the one built internally.")
-
-option(MP_ENABLE_CLANG_TIDY "Run clang-tidy with the compiler." OFF)
-if(MP_ENABLE_CLANG_TIDY)
-  find_program(CLANG_TIDY_EXECUTABLE NAMES clang-tidy)
-  if(NOT CLANG_TIDY_EXECUTABLE)
-    message(FATAL_ERROR "MP_ENABLE_CLANG_TIDY is ON but clang-tidy is not found.")
-  endif()
-  set(CMAKE_CXX_CLANG_TIDY "${CLANG_TIDY_EXECUTABLE}")
-
-  # Workaround for nix from https://gitlab.kitware.com/cmake/cmake/-/issues/20912#note_793338
-  # Nix injects header paths via $NIX_CFLAGS_COMPILE; CMake tags these as
-  # CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES and omits them from the compile
-  # database, so clang-tidy, which ignores $NIX_CFLAGS_COMPILE, can't find capnp
-  # headers. Setting them as standard passes them to clang-tidy.
-  set(CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES ${CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES})
-endif()
-
-option(MP_ENABLE_IWYU "Run include-what-you-use with the compiler." OFF)
-if(MP_ENABLE_IWYU)
-  find_program(IWYU_EXECUTABLE NAMES include-what-you-use iwyu)
-  if(NOT IWYU_EXECUTABLE)
-    message(FATAL_ERROR "MP_ENABLE_IWYU is ON but include-what-you-use was not found.")
-  endif()
-  set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${IWYU_EXECUTABLE};-Xiwyu;--error")
-  if(DEFINED ENV{IWYU_MAPPING_FILE})
-    list(APPEND CMAKE_CXX_INCLUDE_WHAT_YOU_USE "-Xiwyu" "--mapping_file=$ENV{IWYU_MAPPING_FILE}")
-  endif()
-endif()
-
-include("cmake/compat_config.cmake")
-include("cmake/pthread_checks.cmake")
-include(GNUInstallDirs)
-
-# Set MP_INCLUDE_DIR as a global property so target_capnp_sources function can
-# use it, and its callers don't need to specify the include directory manually
-# to avoid "error: Import failed: /mp/proxy.capnp" failures from capnproto.
-set_property(GLOBAL PROPERTY MP_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/include")
-
-# Set a convenience variable for subdirectories.
-if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  set(MP_STANDALONE TRUE)
-  include(CTest)
-else()
-  set(MP_STANDALONE FALSE)
-endif()
-
-# Prevent include directories from parent project from leaking into this one.
-set_property(DIRECTORY PROPERTY INCLUDE_DIRECTORIES "")
-
-# Generated C++ preprocessor defines
-configure_file(include/mp/config.h.in "${CMAKE_CURRENT_BINARY_DIR}/include/mp/config.h")
-
-# Generated C++ Capn'Proto schema files
-capnp_generate_cpp(MP_PROXY_SRCS MP_PROXY_HDRS include/mp/proxy.capnp)
-set_source_files_properties("${MP_PROXY_SRCS}" PROPERTIES SKIP_LINTING TRUE) # Ignored before cmake 3.27
-
-# util library
-add_library(mputil OBJECT src/mp/util.cpp)
-target_include_directories(mputil PRIVATE
-  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-  $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>)
-target_link_libraries(mputil PUBLIC CapnProto::kj)
-
-# libmultiprocess.a runtime library
-set(MP_PUBLIC_HEADERS
-  ${MP_PROXY_HDRS}
-  include/mp/proxy-io.h
-  include/mp/proxy-types.h
-  include/mp/proxy.h
-  include/mp/type-char.h
-  include/mp/type-chrono.h
-  include/mp/type-context.h
-  include/mp/type-data.h
-  include/mp/type-decay.h
-  include/mp/type-exception.h
-  include/mp/type-function.h
-  include/mp/type-interface.h
-  include/mp/type-map.h
-  include/mp/type-message.h
-  include/mp/type-number.h
-  include/mp/type-optional.h
-  include/mp/type-pair.h
-  include/mp/type-pointer.h
-  include/mp/type-set.h
-  include/mp/type-string.h
-  include/mp/type-struct.h
-  include/mp/type-threadmap.h
-  include/mp/type-tuple.h
-  include/mp/type-vector.h
-  include/mp/type-void.h
-  include/mp/util.h)
-add_library(multiprocess STATIC
-  ${MP_PROXY_SRCS}
-  ${MP_PUBLIC_HEADERS}
-  src/mp/proxy.cpp
-  $<TARGET_OBJECTS:mputil>)
-add_library(Libmultiprocess::multiprocess ALIAS multiprocess)
-target_include_directories(multiprocess PUBLIC
-  $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>
-  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-  $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
-target_link_libraries(multiprocess PUBLIC CapnProto::capnp)
-target_link_libraries(multiprocess PUBLIC CapnProto::capnp-rpc)
-target_link_libraries(multiprocess PUBLIC CapnProto::kj)
-target_link_libraries(multiprocess PUBLIC CapnProto::kj-async)
-set_target_properties(multiprocess PROPERTIES
-    PUBLIC_HEADER "${MP_PUBLIC_HEADERS}")
-install(TARGETS multiprocess EXPORT LibTargets
-  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT lib
-  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/mp COMPONENT lib)
-
-# mpgen code generator
-add_executable(mpgen src/mp/gen.cpp $<TARGET_OBJECTS:mputil>)
-add_executable(Libmultiprocess::mpgen ALIAS mpgen)
-target_include_directories(mpgen PRIVATE $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>)
-target_include_directories(mpgen PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include> $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
-target_link_libraries(mpgen PRIVATE CapnProto::capnp)
-target_link_libraries(mpgen PRIVATE CapnProto::capnp-rpc)
-target_link_libraries(mpgen PRIVATE CapnProto::capnpc)
-target_link_libraries(mpgen PRIVATE CapnProto::kj)
-target_link_libraries(mpgen PRIVATE Threads::Threads)
-set_target_properties(mpgen PROPERTIES
-    INSTALL_RPATH_USE_LINK_PATH TRUE)
-set_target_properties(mpgen PROPERTIES
-    PUBLIC_HEADER include/mp/proxy.capnp)
-install(TARGETS mpgen EXPORT BinTargets
-  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT bin
-  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/mp COMPONENT bin)
-
-# makefile include to invoke mpgen code generator, for downstream Make projects
-install(FILES "include/mpgen.mk"
-  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} COMPONENT bin)
-
-# pkg-config module to build against libmultiprocess library, for downstream autoconf projects
-configure_file(pkgconfig/libmultiprocess.pc.in "${CMAKE_CURRENT_BINARY_DIR}/pkgconfig/libmultiprocess.pc" @ONLY)
-install(FILES "${CMAKE_CURRENT_BINARY_DIR}/pkgconfig/libmultiprocess.pc"
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig COMPONENT lib)
-
-# cmake include to invoke mpgen code generator, for downstream CMake projects
-install(
-  FILES
-    ${CMAKE_CURRENT_SOURCE_DIR}/cmake/TargetCapnpSources.cmake
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess COMPONENT bin)
-
-# CMake target import files, for downstream CMake projects
-install(EXPORT BinTargets
-  NAMESPACE Libmultiprocess::
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess COMPONENT bin)
-install(EXPORT LibTargets
-  NAMESPACE Libmultiprocess::
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess COMPONENT lib)
-
-# CMake find_package config file, for downstream CMake projects
-include(CMakePackageConfigHelpers)
-configure_package_config_file(
-  ${PROJECT_SOURCE_DIR}/cmake/Config.cmake.in
-  LibmultiprocessConfig.cmake
-  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess
-  NO_SET_AND_CHECK_MACRO)
-install(
-  FILES
-    ${CMAKE_CURRENT_BINARY_DIR}/LibmultiprocessConfig.cmake
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess
-  COMPONENT common)
-
-# Makefile targets to support "make install-bin" "make install-lib"
-add_custom_target(install-bin
-  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=bin -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
-  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=common -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
-  VERBATIM)
-add_dependencies(install-bin mpgen)
-add_custom_target(install-lib
-  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=lib -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
-  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=common -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
-  VERBATIM)
-add_dependencies(install-lib multiprocess)
 
-# Example and test subdirectories
+add_subdirectory(lib)
 add_subdirectory(example EXCLUDE_FROM_ALL)
-add_subdirectory(test EXCLUDE_FROM_ALL)
diff --git a/ci/scripts/bitcoin_core_ci.sh b/ci/scripts/bitcoin_core_ci.sh
index 7f3c5cbd..cb2283b1 100755
--- a/ci/scripts/bitcoin_core_ci.sh
+++ b/ci/scripts/bitcoin_core_ci.sh
@@ -10,8 +10,10 @@ source "${SCRIPT_DIR}/ci_helpers.sh"
 
 replace_subtree() {
   rm -rf src/ipc/libmultiprocess
-  cp -a _libmultiprocess src/ipc/libmultiprocess
-  rm -rf src/ipc/libmultiprocess/.git
+  # The Bitcoin Core subtree mirrors the contents of the upstream 'lib'
+  # branch, which is 'git subtree split --prefix=lib' of master. Replace the
+  # subtree with the same lib/ contents the split branch would publish.
+  cp -a _libmultiprocess/lib src/ipc/libmultiprocess
 }
 
 add_llvm_apt_repository() {
diff --git a/ci/scripts/ci.sh b/ci/scripts/ci.sh
index d989e9f4..a3bbb22e 100755
--- a/ci/scripts/ci.sh
+++ b/ci/scripts/ci.sh
@@ -21,6 +21,12 @@ cmake --version
 cmake_ver=$(cmake --version | awk '/version/{print $3; exit}')
 ver_ge() { [ "$(printf '%s\n' "$2" "$1" | sort -V | head -n1)" = "$2" ]; }
 
+# The library sources live under lib/ so that 'git subtree split --prefix=lib'
+# produces a 'lib' branch suitable for consumption as a git subtree by
+# downstream projects, without pulling in CI scripts, examples, pkg-config
+# templates, documentation or other upstream-only files. Standalone builds use
+# the top-level CMakeLists.txt wrapper, which adds the example/ subdirectory
+# and pkg-config install rules on top of lib/.
 src_dir=$PWD
 mkdir -p "$CI_DIR"
 cd "$CI_DIR"
diff --git a/example/CMakeLists.txt b/example/CMakeLists.txt
index 7da049c3..6e0541d3 100644
--- a/example/CMakeLists.txt
+++ b/example/CMakeLists.txt
@@ -2,8 +2,6 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-include(${PROJECT_SOURCE_DIR}/cmake/TargetCapnpSources.cmake)
-
 add_executable(mpcalculator
   calculator.cpp
 )
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
new file mode 100644
index 00000000..99b992e7
--- /dev/null
+++ b/lib/CMakeLists.txt
@@ -0,0 +1,276 @@
+# Copyright (c) The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+cmake_minimum_required(VERSION 3.12)
+
+project("Libmultiprocess" CXX)
+if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  set(CMAKE_CXX_STANDARD 20)
+  set(CMAKE_CXX_STANDARD_REQUIRED YES)
+endif()
+
+include("cmake/compat_find.cmake")
+
+find_package(Threads REQUIRED)
+# When this file is processed via add_subdirectory() from the standalone
+# wrapper, find_package(CapnProto) has already been called there to make the
+# IMPORTED targets visible to the example/ sibling directory. Re-running it
+# here would fail on platforms whose CapnProto cmake config registers global
+# targets (e.g. NetBSD pkgsrc), so skip it when CapnProto is already found.
+if(NOT CapnProto_FOUND)
+  find_package(CapnProto 0.7 QUIET NO_MODULE)
+endif()
+ if(NOT CapnProto_FOUND)
+   message(FATAL_ERROR
+     "Cap'n Proto is required but was not found.\n"
+     "To resolve, choose one of the following:\n"
+     "  - Install Cap'n Proto (version 1.0+ recommended)\n"
+     "  - For Bitcoin Core compilation build with -DENABLE_IPC=OFF to disable multiprocess support\n"
+   )
+ endif()
+
+# Cap'n Proto compatibility checks
+set(CAPNPROTO_ISSUES "")
+set(CAPNPROTO_CVE_AFFECTED FALSE)
+set(CAPNPROTO_CLANG_INCOMPATIBLE FALSE)
+
+# Check for list-of-pointers memory access bug from Nov 2022
+# https://nvd.nist.gov/vuln/detail/CVE-2022-46149
+# https://github.com/advisories/GHSA-qqff-4vw4-f6hx
+# https://github.com/capnproto/capnproto/security/advisories/GHSA-qqff-4vw4-f6hx
+# https://github.com/capnproto/capnproto/blob/master/security-advisories/2022-11-30-0-pointer-list-bounds.md
+# https://capnproto.org/news/2022-11-30-CVE-2022-46149-security-advisory.html
+# https://dwrensha.github.io/capnproto-rust/2022/11/30/out_of_bounds_memory_access_bug.html
+if(CapnProto_VERSION STREQUAL "0.7.0"
+   OR CapnProto_VERSION STREQUAL "0.8.0"
+   OR CapnProto_VERSION STREQUAL "0.9.0"
+   OR CapnProto_VERSION STREQUAL "0.9.1"
+   OR CapnProto_VERSION STREQUAL "0.10.0"
+   OR CapnProto_VERSION STREQUAL "0.10.1"
+   OR CapnProto_VERSION STREQUAL "0.10.2")
+  set(CAPNPROTO_CVE_AFFECTED TRUE)
+  string(APPEND CAPNPROTO_ISSUES "- CVE-2022-46149 security vulnerability (details: https://github.com/advisories/GHSA-qqff-4vw4-f6hx)\n")
+endif()
+
+# Check for Cap'n Proto / Clang / C++20 incompatibility
+# Cap'n Proto 0.9.x and 0.10.x are incompatible with Clang 16+ when using C++20
+# due to P2468R2 implementation. This was fixed in Cap'n Proto 1.0+.
+# See: https://github.com/bitcoin-core/libmultiprocess/issues/199
+if((CapnProto_VERSION VERSION_GREATER_EQUAL "0.9.0") AND
+   (CapnProto_VERSION VERSION_LESS "1.0.0") AND
+   (CMAKE_CXX_COMPILER_ID STREQUAL "Clang") AND
+   (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "16") AND
+   (CMAKE_CXX_STANDARD EQUAL 20))
+  set(CAPNPROTO_CLANG_INCOMPATIBLE TRUE)
+  string(APPEND CAPNPROTO_ISSUES "- Incompatible with Clang ${CMAKE_CXX_COMPILER_VERSION} when using C++20\n")
+endif()
+
+if(CAPNPROTO_CVE_AFFECTED OR CAPNPROTO_CLANG_INCOMPATIBLE)
+  set(RESOLUTION_OPTIONS "")
+
+  # Fixes both issues
+  string(APPEND RESOLUTION_OPTIONS "  - Upgrade to Cap'n Proto version 1.0 or newer (recommended)\n")
+
+  if(CAPNPROTO_CVE_AFFECTED AND NOT CAPNPROTO_CLANG_INCOMPATIBLE)
+    string(APPEND RESOLUTION_OPTIONS "  - Upgrade to a patched minor version (0.7.1, 0.8.1, 0.9.2, 0.10.3, or later)\n")
+  elseif(CAPNPROTO_CLANG_INCOMPATIBLE AND NOT CAPNPROTO_CVE_AFFECTED)
+    string(APPEND RESOLUTION_OPTIONS "  - Use GCC instead of Clang\n")
+  endif()
+
+  string(APPEND RESOLUTION_OPTIONS "  - For Bitcoin Core compilation build with -DENABLE_IPC=OFF to disable multiprocess support\n")
+
+  message(FATAL_ERROR
+    "The version of Cap'n Proto detected: ${CapnProto_VERSION} has known compatibility issues:\n"
+    "${CAPNPROTO_ISSUES}"
+    "To resolve, choose one of the following:\n"
+    "${RESOLUTION_OPTIONS}"
+  )
+endif()
+
+set(MPGEN_EXECUTABLE "" CACHE FILEPATH "If specified, should be full path to an external mpgen binary to use rather than the one built internally.")
+
+option(MP_ENABLE_CLANG_TIDY "Run clang-tidy with the compiler." OFF)
+if(MP_ENABLE_CLANG_TIDY)
+  find_program(CLANG_TIDY_EXECUTABLE NAMES clang-tidy)
+  if(NOT CLANG_TIDY_EXECUTABLE)
+    message(FATAL_ERROR "MP_ENABLE_CLANG_TIDY is ON but clang-tidy is not found.")
+  endif()
+  set(CMAKE_CXX_CLANG_TIDY "${CLANG_TIDY_EXECUTABLE}")
+
+  # Workaround for nix from https://gitlab.kitware.com/cmake/cmake/-/issues/20912#note_793338
+  # Nix injects header paths via $NIX_CFLAGS_COMPILE; CMake tags these as
+  # CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES and omits them from the compile
+  # database, so clang-tidy, which ignores $NIX_CFLAGS_COMPILE, can't find capnp
+  # headers. Setting them as standard passes them to clang-tidy.
+  set(CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES ${CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES})
+endif()
+
+option(MP_ENABLE_IWYU "Run include-what-you-use with the compiler." OFF)
+if(MP_ENABLE_IWYU)
+  find_program(IWYU_EXECUTABLE NAMES include-what-you-use iwyu)
+  if(NOT IWYU_EXECUTABLE)
+    message(FATAL_ERROR "MP_ENABLE_IWYU is ON but include-what-you-use was not found.")
+  endif()
+  set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${IWYU_EXECUTABLE};-Xiwyu;--error")
+  if(DEFINED ENV{IWYU_MAPPING_FILE})
+    list(APPEND CMAKE_CXX_INCLUDE_WHAT_YOU_USE "-Xiwyu" "--mapping_file=$ENV{IWYU_MAPPING_FILE}")
+  endif()
+endif()
+
+include("cmake/compat_config.cmake")
+include("cmake/pthread_checks.cmake")
+include("cmake/TargetCapnpSources.cmake")
+include(GNUInstallDirs)
+
+# Set MP_INCLUDE_DIR as a global property so target_capnp_sources function can
+# use it, and its callers don't need to specify the include directory manually
+# to avoid "error: Import failed: /mp/proxy.capnp" failures from capnproto.
+set_property(GLOBAL PROPERTY MP_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/include")
+
+# Set a convenience variable for subdirectories. May be pre-set by a parent
+# CMakeLists.txt (e.g. the top-level wrapper used for `cmake -S .` standalone
+# builds) so that test/ and other subdirectories know they should expose
+# convenience targets even though lib/ is not the top-level source.
+if(NOT DEFINED MP_STANDALONE)
+  if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    set(MP_STANDALONE TRUE)
+    include(CTest)
+  else()
+    set(MP_STANDALONE FALSE)
+  endif()
+endif()
+
+# Prevent include directories from parent project from leaking into this one.
+set_property(DIRECTORY PROPERTY INCLUDE_DIRECTORIES "")
+
+# Generated C++ preprocessor defines
+configure_file(include/mp/config.h.in "${CMAKE_CURRENT_BINARY_DIR}/include/mp/config.h")
+
+# Generated C++ Capn'Proto schema files
+capnp_generate_cpp(MP_PROXY_SRCS MP_PROXY_HDRS include/mp/proxy.capnp)
+set_source_files_properties("${MP_PROXY_SRCS}" PROPERTIES SKIP_LINTING TRUE) # Ignored before cmake 3.27
+
+# util library
+add_library(mputil OBJECT src/mp/util.cpp)
+target_include_directories(mputil PRIVATE
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>)
+target_link_libraries(mputil PUBLIC CapnProto::kj)
+
+# libmultiprocess.a runtime library
+set(MP_PUBLIC_HEADERS
+  ${MP_PROXY_HDRS}
+  include/mp/proxy-io.h
+  include/mp/proxy-types.h
+  include/mp/proxy.h
+  include/mp/type-char.h
+  include/mp/type-chrono.h
+  include/mp/type-context.h
+  include/mp/type-data.h
+  include/mp/type-decay.h
+  include/mp/type-exception.h
+  include/mp/type-function.h
+  include/mp/type-interface.h
+  include/mp/type-map.h
+  include/mp/type-message.h
+  include/mp/type-number.h
+  include/mp/type-optional.h
+  include/mp/type-pair.h
+  include/mp/type-pointer.h
+  include/mp/type-set.h
+  include/mp/type-string.h
+  include/mp/type-struct.h
+  include/mp/type-threadmap.h
+  include/mp/type-tuple.h
+  include/mp/type-vector.h
+  include/mp/type-void.h
+  include/mp/util.h)
+add_library(multiprocess STATIC
+  ${MP_PROXY_SRCS}
+  ${MP_PUBLIC_HEADERS}
+  src/mp/proxy.cpp
+  $<TARGET_OBJECTS:mputil>)
+add_library(Libmultiprocess::multiprocess ALIAS multiprocess)
+target_include_directories(multiprocess PUBLIC
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+  $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+target_link_libraries(multiprocess PUBLIC CapnProto::capnp)
+target_link_libraries(multiprocess PUBLIC CapnProto::capnp-rpc)
+target_link_libraries(multiprocess PUBLIC CapnProto::kj)
+target_link_libraries(multiprocess PUBLIC CapnProto::kj-async)
+set_target_properties(multiprocess PROPERTIES
+    PUBLIC_HEADER "${MP_PUBLIC_HEADERS}")
+install(TARGETS multiprocess EXPORT LibTargets
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT lib
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/mp COMPONENT lib)
+
+# mpgen code generator
+add_executable(mpgen src/mp/gen.cpp $<TARGET_OBJECTS:mputil>)
+add_executable(Libmultiprocess::mpgen ALIAS mpgen)
+target_include_directories(mpgen PRIVATE $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>)
+target_include_directories(mpgen PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include> $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+target_link_libraries(mpgen PRIVATE CapnProto::capnp)
+target_link_libraries(mpgen PRIVATE CapnProto::capnp-rpc)
+target_link_libraries(mpgen PRIVATE CapnProto::capnpc)
+target_link_libraries(mpgen PRIVATE CapnProto::kj)
+target_link_libraries(mpgen PRIVATE Threads::Threads)
+set_target_properties(mpgen PROPERTIES
+    INSTALL_RPATH_USE_LINK_PATH TRUE)
+set_target_properties(mpgen PROPERTIES
+    PUBLIC_HEADER include/mp/proxy.capnp)
+install(TARGETS mpgen EXPORT BinTargets
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT bin
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/mp COMPONENT bin)
+
+# makefile include to invoke mpgen code generator, for downstream Make projects
+install(FILES "include/mpgen.mk"
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR} COMPONENT bin)
+
+# pkg-config module to build against libmultiprocess library, for downstream autoconf projects
+configure_file(pkgconfig/libmultiprocess.pc.in "${CMAKE_CURRENT_BINARY_DIR}/pkgconfig/libmultiprocess.pc" @ONLY)
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/pkgconfig/libmultiprocess.pc"
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig COMPONENT lib)
+
+# cmake include to invoke mpgen code generator, for downstream CMake projects
+install(
+  FILES
+    ${CMAKE_CURRENT_SOURCE_DIR}/cmake/TargetCapnpSources.cmake
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess COMPONENT bin)
+
+# CMake target import files, for downstream CMake projects
+install(EXPORT BinTargets
+  NAMESPACE Libmultiprocess::
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess COMPONENT bin)
+install(EXPORT LibTargets
+  NAMESPACE Libmultiprocess::
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess COMPONENT lib)
+
+# CMake find_package config file, for downstream CMake projects
+include(CMakePackageConfigHelpers)
+configure_package_config_file(
+  ${PROJECT_SOURCE_DIR}/cmake/Config.cmake.in
+  LibmultiprocessConfig.cmake
+  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess
+  NO_SET_AND_CHECK_MACRO)
+install(
+  FILES
+    ${CMAKE_CURRENT_BINARY_DIR}/LibmultiprocessConfig.cmake
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/Libmultiprocess
+  COMPONENT common)
+
+# Makefile targets to support "make install-bin" "make install-lib"
+add_custom_target(install-bin
+  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=bin -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
+  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=common -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
+  VERBATIM)
+add_dependencies(install-bin mpgen)
+add_custom_target(install-lib
+  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=lib -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
+  COMMAND ${CMAKE_COMMAND} -DCOMPONENT=common -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_install.cmake
+  VERBATIM)
+add_dependencies(install-lib multiprocess)
+
+# Test subdirectory
+add_subdirectory(test EXCLUDE_FROM_ALL)
diff --git a/cmake/Config.cmake.in b/lib/cmake/Config.cmake.in
similarity index 100%
rename from cmake/Config.cmake.in
rename to lib/cmake/Config.cmake.in
diff --git a/cmake/TargetCapnpSources.cmake b/lib/cmake/TargetCapnpSources.cmake
similarity index 100%
rename from cmake/TargetCapnpSources.cmake
rename to lib/cmake/TargetCapnpSources.cmake
diff --git a/cmake/compat_config.cmake b/lib/cmake/compat_config.cmake
similarity index 100%
rename from cmake/compat_config.cmake
rename to lib/cmake/compat_config.cmake
diff --git a/cmake/compat_find.cmake b/lib/cmake/compat_find.cmake
similarity index 100%
rename from cmake/compat_find.cmake
rename to lib/cmake/compat_find.cmake
diff --git a/cmake/pthread_checks.cmake b/lib/cmake/pthread_checks.cmake
similarity index 100%
rename from cmake/pthread_checks.cmake
rename to lib/cmake/pthread_checks.cmake
diff --git a/include/mp/config.h.in b/lib/include/mp/config.h.in
similarity index 100%
rename from include/mp/config.h.in
rename to lib/include/mp/config.h.in
diff --git a/include/mp/proxy-io.h b/lib/include/mp/proxy-io.h
similarity index 100%
rename from include/mp/proxy-io.h
rename to lib/include/mp/proxy-io.h
diff --git a/include/mp/proxy-types.h b/lib/include/mp/proxy-types.h
similarity index 100%
rename from include/mp/proxy-types.h
rename to lib/include/mp/proxy-types.h
diff --git a/include/mp/proxy.capnp b/lib/include/mp/proxy.capnp
similarity index 100%
rename from include/mp/proxy.capnp
rename to lib/include/mp/proxy.capnp
diff --git a/include/mp/proxy.h b/lib/include/mp/proxy.h
similarity index 100%
rename from include/mp/proxy.h
rename to lib/include/mp/proxy.h
diff --git a/include/mp/type-char.h b/lib/include/mp/type-char.h
similarity index 100%
rename from include/mp/type-char.h
rename to lib/include/mp/type-char.h
diff --git a/include/mp/type-chrono.h b/lib/include/mp/type-chrono.h
similarity index 100%
rename from include/mp/type-chrono.h
rename to lib/include/mp/type-chrono.h
diff --git a/include/mp/type-context.h b/lib/include/mp/type-context.h
similarity index 100%
rename from include/mp/type-context.h
rename to lib/include/mp/type-context.h
diff --git a/include/mp/type-data.h b/lib/include/mp/type-data.h
similarity index 100%
rename from include/mp/type-data.h
rename to lib/include/mp/type-data.h
diff --git a/include/mp/type-decay.h b/lib/include/mp/type-decay.h
similarity index 100%
rename from include/mp/type-decay.h
rename to lib/include/mp/type-decay.h
diff --git a/include/mp/type-exception.h b/lib/include/mp/type-exception.h
similarity index 100%
rename from include/mp/type-exception.h
rename to lib/include/mp/type-exception.h
diff --git a/include/mp/type-function.h b/lib/include/mp/type-function.h
similarity index 100%
rename from include/mp/type-function.h
rename to lib/include/mp/type-function.h
diff --git a/include/mp/type-interface.h b/lib/include/mp/type-interface.h
similarity index 100%
rename from include/mp/type-interface.h
rename to lib/include/mp/type-interface.h
diff --git a/include/mp/type-map.h b/lib/include/mp/type-map.h
similarity index 100%
rename from include/mp/type-map.h
rename to lib/include/mp/type-map.h
diff --git a/include/mp/type-message.h b/lib/include/mp/type-message.h
similarity index 100%
rename from include/mp/type-message.h
rename to lib/include/mp/type-message.h
diff --git a/include/mp/type-number.h b/lib/include/mp/type-number.h
similarity index 100%
rename from include/mp/type-number.h
rename to lib/include/mp/type-number.h
diff --git a/include/mp/type-optional.h b/lib/include/mp/type-optional.h
similarity index 100%
rename from include/mp/type-optional.h
rename to lib/include/mp/type-optional.h
diff --git a/include/mp/type-pair.h b/lib/include/mp/type-pair.h
similarity index 100%
rename from include/mp/type-pair.h
rename to lib/include/mp/type-pair.h
diff --git a/include/mp/type-pointer.h b/lib/include/mp/type-pointer.h
similarity index 100%
rename from include/mp/type-pointer.h
rename to lib/include/mp/type-pointer.h
diff --git a/include/mp/type-set.h b/lib/include/mp/type-set.h
similarity index 100%
rename from include/mp/type-set.h
rename to lib/include/mp/type-set.h
diff --git a/include/mp/type-string.h b/lib/include/mp/type-string.h
similarity index 100%
rename from include/mp/type-string.h
rename to lib/include/mp/type-string.h
diff --git a/include/mp/type-struct.h b/lib/include/mp/type-struct.h
similarity index 100%
rename from include/mp/type-struct.h
rename to lib/include/mp/type-struct.h
diff --git a/include/mp/type-threadmap.h b/lib/include/mp/type-threadmap.h
similarity index 100%
rename from include/mp/type-threadmap.h
rename to lib/include/mp/type-threadmap.h
diff --git a/include/mp/type-tuple.h b/lib/include/mp/type-tuple.h
similarity index 100%
rename from include/mp/type-tuple.h
rename to lib/include/mp/type-tuple.h
diff --git a/include/mp/type-vector.h b/lib/include/mp/type-vector.h
similarity index 100%
rename from include/mp/type-vector.h
rename to lib/include/mp/type-vector.h
diff --git a/include/mp/type-void.h b/lib/include/mp/type-void.h
similarity index 100%
rename from include/mp/type-void.h
rename to lib/include/mp/type-void.h
diff --git a/include/mp/util.h b/lib/include/mp/util.h
similarity index 100%
rename from include/mp/util.h
rename to lib/include/mp/util.h
diff --git a/include/mp/version.h b/lib/include/mp/version.h
similarity index 100%
rename from include/mp/version.h
rename to lib/include/mp/version.h
diff --git a/include/mpgen.mk b/lib/include/mpgen.mk
similarity index 100%
rename from include/mpgen.mk
rename to lib/include/mpgen.mk
diff --git a/pkgconfig/libmultiprocess.pc.in b/lib/pkgconfig/libmultiprocess.pc.in
similarity index 100%
rename from pkgconfig/libmultiprocess.pc.in
rename to lib/pkgconfig/libmultiprocess.pc.in
diff --git a/src/mp/gen.cpp b/lib/src/mp/gen.cpp
similarity index 100%
rename from src/mp/gen.cpp
rename to lib/src/mp/gen.cpp
diff --git a/src/mp/proxy.cpp b/lib/src/mp/proxy.cpp
similarity index 100%
rename from src/mp/proxy.cpp
rename to lib/src/mp/proxy.cpp
diff --git a/src/mp/util.cpp b/lib/src/mp/util.cpp
similarity index 100%
rename from src/mp/util.cpp
rename to lib/src/mp/util.cpp
diff --git a/test/CMakeLists.txt b/lib/test/CMakeLists.txt
similarity index 96%
rename from test/CMakeLists.txt
rename to lib/test/CMakeLists.txt
index 1f21ba44..097bc8c5 100644
--- a/test/CMakeLists.txt
+++ b/lib/test/CMakeLists.txt
@@ -29,7 +29,7 @@ if(BUILD_TESTING AND TARGET CapnProto::kj-test)
     mp/test/spawn_tests.cpp
     mp/test/test.cpp
   )
-  include(${PROJECT_SOURCE_DIR}/cmake/TargetCapnpSources.cmake)
+
   target_capnp_sources(mptest ${CMAKE_CURRENT_SOURCE_DIR} mp/test/foo.capnp)
   target_include_directories(mptest PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
   target_link_libraries(mptest PRIVATE CapnProto::kj-test)
diff --git a/test/mp/test/foo-types.h b/lib/test/mp/test/foo-types.h
similarity index 100%
rename from test/mp/test/foo-types.h
rename to lib/test/mp/test/foo-types.h
diff --git a/test/mp/test/foo.capnp b/lib/test/mp/test/foo.capnp
similarity index 100%
rename from test/mp/test/foo.capnp
rename to lib/test/mp/test/foo.capnp
diff --git a/test/mp/test/foo.h b/lib/test/mp/test/foo.h
similarity index 100%
rename from test/mp/test/foo.h
rename to lib/test/mp/test/foo.h
diff --git a/test/mp/test/spawn_tests.cpp b/lib/test/mp/test/spawn_tests.cpp
similarity index 100%
rename from test/mp/test/spawn_tests.cpp
rename to lib/test/mp/test/spawn_tests.cpp
diff --git a/test/mp/test/test.cpp b/lib/test/mp/test/test.cpp
similarity index 100%
rename from test/mp/test/test.cpp
rename to lib/test/mp/test/test.cpp

From 66d7b4871d47e77e89c80cb691436f4f86974971 Mon Sep 17 00:00:00 2001
From: Sjors Provoost <sjors@sprovoost.nl>
Date: Tue, 12 May 2026 11:48:40 +0200
Subject: [PATCH 2/2] ci: drop Bitcoin Core example-target reference during
 subtree replace

Bitcoin Core's cmake/libmultiprocess.cmake currently references the
mpcalculator, mpprinter and mpexample targets, which no longer exist
in the subtree (the example/ directory lives outside the 'lib' branch).

Strip the offending line as part of replace_subtree so the bitcoin-core
CI job configures cleanly. Remove this workaround once a matching
Bitcoin Core PR has landed.
---
 ci/scripts/bitcoin_core_ci.sh | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/ci/scripts/bitcoin_core_ci.sh b/ci/scripts/bitcoin_core_ci.sh
index cb2283b1..1843b357 100755
--- a/ci/scripts/bitcoin_core_ci.sh
+++ b/ci/scripts/bitcoin_core_ci.sh
@@ -14,6 +14,13 @@ replace_subtree() {
   # branch, which is 'git subtree split --prefix=lib' of master. Replace the
   # subtree with the same lib/ contents the split branch would publish.
   cp -a _libmultiprocess/lib src/ipc/libmultiprocess
+  # The example/ directory is intentionally not part of the 'lib' branch, so
+  # the mpcalculator/mpprinter/mpexample targets do not exist. Drop the line
+  # in Bitcoin Core's cmake glue that references them. Remove this once
+  # Bitcoin Core no longer references the example targets. Use perl -ni
+  # rather than 'sed -i' so this works on both GNU and BSD sed (macOS).
+  perl -ni -e 'print unless /set_target_properties\(mpcalculator mpprinter mpexample/' \
+    cmake/libmultiprocess.cmake
 }
 
 add_llvm_apt_repository() {