Update build documentation

doc/build-cross.md

@@ -0,0 +1,95 @@
+Cross-compiliation of Dash Core
+===============================
+
+Dash Core can be cross-compiled on Linux to all other supported host systems. This is done by changing
+the `HOST` parameter when building the dependencies and then specifying another `--prefix` directory when building Dash.
+
+The following instructions are only tested on Debian Stretch and Ubuntu Bionic.
+
+MacOSX Cross-compilation
+------------------------
+Cross-compiling to MacOSX requires a few additional packages to be installed:
+
+```bash
+$ sudo apt-get install python3-setuptools libcap-dev zlib1g-dev libbz2-dev
+```
+
+Additionally, the Mac OSX SDK must be downloaded and extracted manually:
+
+```bash
+$ mkdir -p depends/sdk-sources
+$ mkdir -p depends/SDKs
+$ curl https://bitcoincore.org/depends-sources/sdks/MacOSX10.11.sdk.tar.gz -o depends/sdk-sources/MacOSX10.11.sdk.tar.gz
+$ tar -C depends/SDKs -xf depends/sdk-sources/MacOSX10.11.sdk.tar.gz
+```
+
+When building the dependencies, as described in [build-generic](build-generic.md), use
+
+```bash
+$ make HOST=x86_64-apple-darwin11 -j4
+```
+
+When building Dash Core, use
+
+```bash
+$ ./configure --prefix `pwd`/depends/x86_64-apple-darwin11
+```
+
+Windows 64bit/32bit Cross-compilation
+-------------------------------
+Cross-compiling to Windows requires a few additional packages to be installed:
+
+```bash
+$ sudo apt-get install nsis wine wine64 bc
+```
+
+For Windows 64bit, install :
+```bash
+$ sudo apt-get install g++-mingw-w64-x86-64
+$ # Required to enable C++ threading libraries (e.g. std::thread)
+$ sudo update-alternatives --set x86_64-w64-mingw32-g++  /usr/bin/x86_64-w64-mingw32-g++-posix
+$ sudo update-alternatives --set x86_64-w64-mingw32-gcc  /usr/bin/x86_64-w64-mingw32-gcc-posix
+```
+
+For Windows 32bit, install:
+```bash
+$ sudo apt-get install g++-mingw-w64-i686
+$ # Required to enable C++ threading libraries (e.g. std::thread)
+$ sudo update-alternatives --set i686-w64-mingw32-gcc /usr/bin/i686-w64-mingw32-gcc-posix
+$ sudo update-alternatives --set i686-w64-mingw32-g++  /usr/bin/i686-w64-mingw32-g++-posix
+```
+
+When building the dependencies, as described in [build-generic](build-generic.md), use
+
+```bash
+$ make HOST=x86_64-w64-mingw32 -j4
+```
+
+When building Dash Core, use
+
+```bash
+$ ./configure --prefix `pwd`/depends/x86_64-w64-mingw32
+```
+
+These commands will build for Windows 64bit. If you want to compile for 32bit,
+replace `x86_64-w64-mingw32` with `i686-w64-mingw32`.
+
+ARM-Linux Cross-compilation
+-------------------
+Cross-compiling to ARM-Linux requires a few additional packages to be installed:
+
+```bash
+$ sudo apt-get install g++-arm-linux-gnueabihf
+```
+
+When building the dependencies, as described in [build-generic](build-generic.md), use
+
+```bash
+$ make HOST=arm-linux-gnueabihf -j4
+```
+
+When building Dash Core, use
+
+```bash
+$ ./configure --prefix `pwd`/depends/arm-linux-gnueabihf
+```

doc/build-generic.md

@@ -0,0 +1,79 @@
+GENERIC BUILD NOTES
+====================
+Some notes on how to build Dash Core based on the [depends](../depends/README.md) build system.
+
+Note on old build instructions
+------------------------------
+In the past, the build documentation contained instructions on how to build Dash with system-wide installed dependencies
+like BerkeleyDB 4.8, boost and Qt. Building this way is considered deprecated and only building with the `depends` prefix
+is supported today.
+
+Required build tools and environment
+------------------------------------
+Building the dependencies and Dash Core requires some essential build tools to be installed before. Please see
+[build-unix](build-unix.md), [build-osx](build-osx.md) and [build-windows](build-windows.md) for details.
+
+Building dependencies
+---------------------
+Dash inherited the `depends` folder from Bitcoin, which contains all dependencies required to build Dash. These
+dependencies must be built before Dash can actually be built. To do so, perform the following:
+
+```bash
+$ cd depends
+$ make -j4 # Choose a good -j value, depending on the number of CPU cores available
+$ cd ..
+```
+
+This will download and build all dependencies required to build Dash Core. Caching of build results will ensure that only
+the packages are rebuilt which have changed since the last depends build.
+
+It is required to re-run the above commands from time to time when dependencies have been updated or added. If this is
+not done, build failures might occur when building Dash.
+
+Please read the [depends](../depends/README.md) documentation for more details on supported hosts and configuration
+options. If no host is specified (as in the above example) when calling `make`, the depends system will default to your
+local host system. 
+
+Building Dash Core
+---------------------
+
+```bash
+$ ./autogen.sh
+$ ./configure --prefix `pwd`/depends/<host>
+$ make
+$ make install # optional
+```
+
+Please replace `<host>` with your local system's `host-platform-triplet`. The following triplets are usually valid:
+- `i686-pc-linux-gnu` for Linux32
+- `x86_64-pc-linux-gnu` for Linux64
+- `i686-w64-mingw32` for Win32
+- `x86_64-w64-mingw32` for Win64
+- `x86_64-apple-darwin11` for MacOSX
+- `arm-linux-gnueabihf` for Linux ARM 32 bit
+- `aarch64-linux-gnu` for Linux ARM 64 bit
+
+If you want to cross-compile for another platform, choose the appropriate `<host>` and make sure to build the
+dependencies with the same host before.
+
+
+ccache
+------
+The depends system also contains [ccache](https://ccache.samba.org/), which caches build results on source->object
+level. `./configure` of Dash Core will autodetect the presence of ccache and enable use of it. To disable ccache, use
+`./configure --prefix=<prefix> --disable-ccache`.
+
+The default maximum cache size is 5G, which might not be enough to cache multiple builds when switching Git branches
+very often. It is advised to increase the maximum cache size:
+
+```bash
+$ ./depends/<host>/bin/ccache -M20G
+```
+
+Additional Configure Flags
+--------------------------
+A list of additional configure flags can be displayed with:
+
+```bash
+./configure --help
+```

doc/build-osx.md

@@ -13,42 +13,22 @@ When the popup appears, click `Install`.
 
 Then install [Homebrew](https://brew.sh).
 
-Dependencies
-----------------------
+Base build dependencies
+-----------------------
 
-    brew install automake berkeley-db4 libtool boost --c++11 miniupnpc openssl pkg-config protobuf qt libevent
+```bash
+brew install automake libtool --c++11 pkg-config
+```
 
 If you want to build the disk image with `make deploy` (.dmg / optional), you need RSVG
+```bash
+brew install librsvg
+```
 
-    brew install librsvg
+Building
+--------
 
-NOTE: Building with Qt4 is still supported, however, doing so could result in a broken UI. Therefore, building with Qt5 is recommended.
-
-Build Dash Core
-------------------------
-
-1. Clone the Dash Core source code and cd into `dash`
-
-        git clone https://github.com/dashpay/dash
-        cd dash
-
-2.  Build Dash Core:
-
-    Configure and build the headless dash binaries as well as the GUI (if Qt is found).
-
-    You can disable the GUI build by passing `--without-gui` to configure.
-
-        ./autogen.sh
-        ./configure
-        make
-
-3.  It is recommended to build and run the unit tests:
-
-        make check
-
-4.  You can also create a .dmg that contains the .app bundle (optional):
-
-        make deploy
+Follow the instructions in [build-generic](build-generic.md)
 
 Running
 -------
@@ -90,10 +70,3 @@ Uncheck everything except Qt Creator during the installation process.
 8. Select the default "Desktop" kit and select "Clang (x86 64bit in /usr/bin)" as compiler
 9. Select LLDB as debugger (you might need to set the path to your installation)
 10. Start debugging with Qt Creator
-
-Notes
------
-
-* Tested on OS X 10.8 through 10.12 on 64-bit Intel processors only.
-
-* Building with downloaded Qt binaries is not officially supported. See the notes in [#7714](https://github.com/bitcoin/bitcoin/issues/7714)