zlib-ng-no-cmake-experimental-community-maintained breaks OSX builds

[brainstorm]

Reproducer: wcampbell0x2a/backhand#651

[Byron]

I can reproduce it here as well:

> cargo build --no-default-features --features "zlib-ng-no-cmake-experimental-community-maintained"
   Compiling libz-sys v1.1.20 (/Users/byron/dev/github.com/rust-lang/libz-sys)
The following warnings were emitted during compilation:

warning: libz-sys@1.1.20: In file included from src/zlib-ng/arch/arm/adler32_neon.c:9:
warning: libz-sys@1.1.20: src/zlib-ng/arch/arm/neon_intrins.h:38:28: error: expected identifier or '('
warning: libz-sys@1.1.20:    38 | static inline uint16x8x4_t vld1q_u16_x4(uint16_t const *a) {
warning: libz-sys@1.1.20:       |                            ^
warning: libz-sys@1.1.20: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include/arm_neon.h:10523:28: note: expanded from macro 'vld1q_u16_x4'
warning: libz-sys@1.1.20:  10523 | #define vld1q_u16_x4(__p0) __extension__ ({ \
warning: libz-sys@1.1.20:        |                            ^
warning: libz-sys@1.1.20: In file included from src/zlib-ng/arch/arm/adler32_neon.c:9:
warning: libz-sys@1.1.20: src/zlib-ng/arch/arm/neon_intrins.h:47:28: error: expected identifier or '('
warning: libz-sys@1.1.20:    47 | static inline uint8x16x4_t vld1q_u8_x4(uint8_t const *a) {
warning: libz-sys@1.1.20:       |                            ^
warning: libz-sys@1.1.20: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include/arm_neon.h:10466:27: note: expanded from macro 'vld1q_u8_x4'
warning: libz-sys@1.1.20:  10466 | #define vld1q_u8_x4(__p0) __extension__ ({ \
warning: libz-sys@1.1.20:        |                           ^
warning: libz-sys@1.1.20: In file included from src/zlib-ng/arch/arm/adler32_neon.c:9:
warning: libz-sys@1.1.20: src/zlib-ng/arch/arm/neon_intrins.h:56:20: error: expected identifier or '('
warning: libz-sys@1.1.20:    56 | static inline void vst1q_u16_x4(uint16_t *p, uint16x8x4_t a) {
warning: libz-sys@1.1.20:       |                    ^
warning: libz-sys@1.1.20: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include/arm_neon.h:28041:34: note: expanded from macro 'vst1q_u16_x4'
warning: libz-sys@1.1.20:  28041 | #define vst1q_u16_x4(__p0, __p1) __extension__ ({ \
warning: libz-sys@1.1.20:        |                                  ^
warning: libz-sys@1.1.20: 3 errors generated.

error: failed to run custom build command for `libz-sys v1.1.20 (/Users/byron/dev/github.com/rust-lang/libz-sys)`

Caused by:
  process didn't exit successfully: `/Users/byron/dev/github.com/rust-lang/libz-sys/target/debug/build/libz-sys-8fef32cd983887a1/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=LIBZ_SYS_STATIC
  cargo:rerun-if-changed=build.rs
  cargo:rerun-if-changed=zng/cmake.rs
  cargo:rerun-if-changed=zng/cc.rs
  OPT_LEVEL = Some(0)
  TARGET = Some(aarch64-apple-darwin)
  HOST = Some(aarch64-apple-darwin)
  cargo:rerun-if-env-changed=CC_aarch64-apple-darwin
  CC_aarch64-apple-darwin = None
  cargo:rerun-if-env-changed=CC_aarch64_apple_darwin
  CC_aarch64_apple_darwin = None
  cargo:rerun-if-env-changed=HOST_CC
  HOST_CC = None
  cargo:rerun-if-env-changed=CC
  CC = None
  cargo:rerun-if-env-changed=CC_ENABLE_DEBUG_OUTPUT
  RUSTC_WRAPPER = None
  cargo:rerun-if-env-changed=CRATE_CC_NO_DEFAULTS
  CRATE_CC_NO_DEFAULTS = None
  DEBUG = Some(true)
  cargo:rerun-if-env-changed=MACOSX_DEPLOYMENT_TARGET
  MACOSX_DEPLOYMENT_TARGET = None
  cargo:rerun-if-env-changed=CFLAGS_aarch64-apple-darwin
  CFLAGS_aarch64-apple-darwin = None
  cargo:rerun-if-env-changed=CFLAGS_aarch64_apple_darwin
  CFLAGS_aarch64_apple_darwin = None
  cargo:rerun-if-env-changed=HOST_CFLAGS
  HOST_CFLAGS = None
  cargo:rerun-if-env-changed=CFLAGS
  CFLAGS = None
  cargo:warning=In file included from src/zlib-ng/arch/arm/adler32_neon.c:9:
  cargo:warning=src/zlib-ng/arch/arm/neon_intrins.h:38:28: error: expected identifier or '('
  cargo:warning=   38 | static inline uint16x8x4_t vld1q_u16_x4(uint16_t const *a) {
  cargo:warning=      |                            ^
  cargo:warning=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include/arm_neon.h:10523:28: note: expanded from macro 'vld1q_u16_x4'
  cargo:warning= 10523 | #define vld1q_u16_x4(__p0) __extension__ ({ \
  cargo:warning=       |                            ^
  cargo:warning=In file included from src/zlib-ng/arch/arm/adler32_neon.c:9:
  cargo:warning=src/zlib-ng/arch/arm/neon_intrins.h:47:28: error: expected identifier or '('
  cargo:warning=   47 | static inline uint8x16x4_t vld1q_u8_x4(uint8_t const *a) {
  cargo:warning=      |                            ^
  cargo:warning=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include/arm_neon.h:10466:27: note: expanded from macro 'vld1q_u8_x4'
  cargo:warning= 10466 | #define vld1q_u8_x4(__p0) __extension__ ({ \
  cargo:warning=       |                           ^
  cargo:warning=In file included from src/zlib-ng/arch/arm/adler32_neon.c:9:
  cargo:warning=src/zlib-ng/arch/arm/neon_intrins.h:56:20: error: expected identifier or '('
  cargo:warning=   56 | static inline void vst1q_u16_x4(uint16_t *p, uint16x8x4_t a) {
  cargo:warning=      |                    ^
  cargo:warning=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include/arm_neon.h:28041:34: note: expanded from macro 'vst1q_u16_x4'
  cargo:warning= 28041 | #define vst1q_u16_x4(__p0, __p1) __extension__ ({ \
  cargo:warning=       |                                  ^
  cargo:warning=3 errors generated.

  --- stderr
  ToolExecError: Command env -u IPHONEOS_DEPLOYMENT_TARGET "cc" "-O0" "-ffunction-sections" "-fdata-sections" "-fPIC" "-gdwarf-2" "-fno-omit-frame-pointer" "--target=arm64-apple-darwin" "-mmacosx-version-min=15.1" "-std=c11" "-I" "/Users/byron/dev/github.com/rust-lang/libz-sys/target/debug/build/libz-sys-8b98d619a1b7a753/out/include" "-I" "src/zlib-ng" "-Werror-implicit-function-declaration" "-fvisibility=hidden" "-march=armv8-a+crc+simd" "-DZLIB_COMPAT" "-DWITH_GZFILEOP" "-DHAVE_ALIGNED_ALLOC" "-DHAVE_ATTRIBUTE_ALIGNED" "-DHAVE_BUILTIN_CTZ" "-DHAVE_BUILTIN_CTZLL" "-DHAVE_THREAD_LOCAL" "-DHAVE_VISIBILITY_HIDDEN" "-DHAVE_VISIBILITY_INTERNAL" "-D_LARGEFILE64_SOURCE=1" "-D__USE_LARGEFILE64" "-DSTDC" "-D_POSIX_SOURCE" "-DHAVE_POSIX_MEMALIGN" "-D_C99_SOURCE" "-DARM_FEATURES" "-DARM_ACLE" "-DHAVE_ARM_ACLE_H" "-DARM_NEON" "-o" "/Users/byron/dev/github.com/rust-lang/libz-sys/target/debug/build/libz-sys-8b98d619a1b7a753/out/lib/1b0507d0191b23d7-adler32_neon.o" "-c" "src/zlib-ng/arch/arm/adler32_neon.c" with args cc did not execute successfully (status code exit status: 1).
  thread 'main' panicked at zng/cc.rs:452:9:
  failed to compile zlib-ng with cc: detected compiler version as
  ---
  Apple clang version 16.0.0 (clang-1600.0.26.4)
  Target: arm64-apple-darwin24.1.0
  Thread model: posix
  InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
  ---
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

CC @Jake-Shadle , maybe there is an easy fix.

[Jake-Shadle]

#231 just disables neon intrinsics since I don't have the time to look at this at the moment.

[Byron]

Thanks a lot for the workaround - I could verify that it does compile now, even though the generated code probably won't be the fastest unless somebody tries to find the true source of the problem.

The issue can probably be closed now.