Cross Compiling a Host Toolchain

This plugin demonstrates a minimal working toolchain built with MXE to execute on a Windows host.

GCC

make gcc-host MXE_PLUGIN_DIRS=plugins/examples/host-toolchain/

This will run the usual steps to build a cross-compiler, then build a second pass to cross-compile the basic toolchain (binutils and gcc).

Once complete, copy usr/{target} to an appropriate Windows machine and execute the usr\{target}\bin\test-gcc-host.bat batch file. This builds and runs the libgomp test as a sanity check. The cross and host built programs should be identical (after stripping), confirmed with the final step:

>fc /b test-gcc-host.exe test-pthreads-libgomp.exe
Comparing files test-gcc-host.exe and TEST-PTHREADS-LIBGOMP.EXE
FC: no differences encountered

CMake

make cmake-host MXE_PLUGIN_DIRS=plugins/examples/host-toolchain/

CMake is made to default to Unix Makefiles generator and additional configuration is required for MinGW or MSYS Makefiles. MinGW uses cmd.exe and requires mingw32-make, MSYS uses make and requires /bin/sh. The latter is recommended for further investigation since it's closest to the normal environment MXE expects. See the following projects for shells and terminal emulators:

• MSYS2
• Git for Windows - uses MSYS2
• ConEmu - usable terminal
• cmder - bundles ConEmu and Git

Make

make make-host MXE_PLUGIN_DIRS=plugins/examples/host-toolchain/

This will cross-compile GNU Make from source (without guile support).

pkgconf/pkg-config

make pkgconf-host MXE_PLUGIN_DIRS=plugins/examples/host-toolchain/

This will cross-compile pkgconf and create the pkg-config wrapper. The wrapper requires /bin/sh so one of the MSYS2 options should be used. Run the usr/{target}/bin/test-pkgconf-host script to build libffi test with non-standard include paths.

Qt5 tools (qmake.exe, rcc.exe, etc.)

make qt5-host-tools MXE_PLUGIN_DIRS=plugins/examples/host-toolchain/

This will build qtbase and cross-compile the toolchain/qt tools/make

On a windows machine, execute usr\{target}\qt5\test-qt5-host-tools\test-qt5-host-tools.bat to build and confirm the normal qt test with the cross-compiled qtbase libraries.

Why?

Simply for curiosity, it's hard to see a practical use for this. Certainly, attempting to use it as a way to bootstrap MXE on Windows would strain one's sanity and cross-compiling is the recommended way (even if that means running a Linux VM on Windows).