cmake toolchain file for mingw-w64 x86_64 builds on Ubuntu

mingw-w64-x86_64.cmake

# Sample toolchain file for building for Windows from an Ubuntu Linux system.
#
# Typical usage:
#    *) install cross compiler: `sudo apt-get install mingw-w64`
#    *) cd build
#    *) cmake -DCMAKE_TOOLCHAIN_FILE=~/mingw-w64-x86_64.cmake ..
# This is free and unencumbered software released into the public domain.

set(CMAKE_SYSTEM_NAME Windows)
set(TOOLCHAIN_PREFIX x86_64-w64-mingw32)

# cross compilers to use for C, C++ and Fortran
set(CMAKE_C_COMPILER ${TOOLCHAIN_PREFIX}-gcc)
set(CMAKE_CXX_COMPILER ${TOOLCHAIN_PREFIX}-g++)
set(CMAKE_Fortran_COMPILER ${TOOLCHAIN_PREFIX}-gfortran)
set(CMAKE_RC_COMPILER ${TOOLCHAIN_PREFIX}-windres)

# target environment on the build host system
set(CMAKE_FIND_ROOT_PATH /usr/${TOOLCHAIN_PREFIX})

# modify default behavior of FIND_XXX() commands
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

Thank you for this! It's also worth to take a look at CMAKE_FIND_ROOT_PATH_MODE_PROGRAM in which as per CMake documentation, setting to NEVER wouldn't search for library in what set in CMAKE_FIND_ROOT_PATH. I tested cross-compile CMake 3.16.x and 3.20.5 on Ubuntu 20.04 and with original configuration as above, find_package(Curses) won't be able to find the library.

I commented the last 3 lines and it is able to find ncurses library.

Anyway, thanks for this. It is useful +1

Wow, this was a lifesaver... for anyone new to cmake just make sure to delete the "cmakecache.txt" file before trying this...

thanks random ppl on the internet

Thank you.

Would you mind releasing this into the public domain or licensing it under a FOSS license and including that in the script?

Would you mind releasing this into the public domain or licensing it under a FOSS license and including that in the script?

Hope that suffices.

@peterspackman Thank you so much for your contribution and for taking the time to do that!

If using pkg-config, you also need to do something like set(PKG_CONFIG_EXECUTABLE ${TOOLCHAIN_PREFIX}-pkg-config) so that FindPkgConfig searches for cross compiled packages, not those for running where cmake is running.

I had dependencies also checking for CMAKE_SYSTEM_PROCESSOR, I believe this line should be added:

set(CMAKE_SYSTEM_PROCESSOR x86_64)

This is immensely helpful. Thank you so much.