wrappers: add CMake toolchain files

Those toolchain files greatly simplify configuring a project
to use the llvm-mingw toolchain.

install-wrappers.sh

@@ -137,6 +137,19 @@ if [ -n "$EXEEXT" ]; then
 else
     CTW_SUFFIX=.sh
 fi
+toolchainfile_path=share/cmake; toolchainfile_rev=../..
+mkdir -p "$PREFIX/$toolchainfile_path"
+sed "s,@RELPATH@,$toolchainfile_rev,g" wrappers/llvm-mingw_toolchainfile.cmake.in >"$PREFIX/$toolchainfile_path/llvm-mingw_toolchainfile.cmake"
+for target_os in $TARGET_OSES; do
+    templ=
+    [ $target_os = mingw32 ] && templ=wrappers/llvm-mingw_toolchainfile_arch.cmake.in
+    [ $target_os = mingw32uwp ] && templ=wrappers/llvm-mingw_toolchainfile_arch_uwp.cmake.in
+    [ -n "$templ" ] || continue
+
+    for arch in $ARCHS; do
+        sed "s,@ARCH@,${arch},g" $templ >"$PREFIX/$toolchainfile_path/${arch}-w64-${target_os}_toolchainfile.cmake"
+    done
+done
 cd "$PREFIX/bin"
 for arch in $ARCHS; do
     for target_os in $TARGET_OSES; do

wrappers/llvm-mingw_toolchainfile.cmake.in

@@ -0,0 +1,84 @@
+if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.20")
+  set(_prefix "${CMAKE_CURRENT_LIST_DIR}/@RELPATH@/")
+  cmake_path(ABSOLUTE_PATH _prefix NORMALIZE)
+else()
+  get_filename_component(_prefix "${CMAKE_CURRENT_LIST_DIR}/@RELPATH@/" ABSOLUTE)
+endif()
+
+if(NOT CMAKE_SYSTEM_NAME)
+  set(CMAKE_SYSTEM_NAME Windows)
+endif()
+if(NOT CMAKE_SYSTEM_PROCESSOR)
+  set(CMAKE_SYSTEM_PROCESSOR ${CMAKE_HOST_SYSTEM_PROCESSOR})
+endif()
+
+set(CMAKE_SYSROOT "${_prefix}${CMAKE_SYSTEM_PROCESSOR}-w64-mingw32")
+
+set(ENV{PKG_CONFIG_SYSROOT_DIR} "${CMAKE_SYSROOT}")
+if($ENV{PKG_CONFIG_LIBDIR})
+  set(ENV{PKG_CONFIG_LIBDIR} "${CMAKE_SYSROOT}/usr/lib/pkgconfig:${CMAKE_SYSROOT}/usr/share/pkgconfig:$ENV{PKG_CONFIG_LIBDIR}")
+else()
+  set(ENV{PKG_CONFIG_LIBDIR} "${CMAKE_SYSROOT}/usr/lib/pkgconfig:${CMAKE_SYSROOT}/usr/share/pkgconfig")
+endif()
+
+# set these before find_program!
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+
+# search tools in prefix, then in system search paths
+# note that the toolchain will be sourced multiple times and stuff like
+# CMAKE_C_COMPILER might be cached - use temp variables with find_program
+set(_linker lld)
+find_program(_clang_exe clang HINTS "${_prefix}bin" NO_CMAKE_PATH NO_CMAKE_ENVIRONMENT_PATH NO_CACHE )
+find_program(_clangp_exe clang++ HINTS "${_prefix}bin" NO_CMAKE_PATH NO_CMAKE_ENVIRONMENT_PATH NO_CACHE)
+find_program(_llvm_rc llvm-rc HINTS "${_prefix}bin" NO_CMAKE_PATH NO_CMAKE_ENVIRONMENT_PATH NO_CACHE) 
+find_program(_ld_linker ld.${_linker} HINTS "${_prefix}bin" NO_CMAKE_PATH NO_CMAKE_ENVIRONMENT_PATH NO_CACHE)
+
+if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.20")
+  cmake_path(GET _clang_exe PARENT_PATH _clang_path)
+else()
+  get_filename_component(_clang_path "${_clang_exe}" DIRECTORY)
+endif()
+
+# test if the system compiler is used 
+if(_clang_path STREQUAL "${_prefix}bin")
+  set(CMAKE_ASM_COMPILER "${_clang_exe}")
+  set(CMAKE_C_COMPILER "${_clang_exe}")
+  set(CMAKE_CXX_COMPILER "${_clangp_exe}")
+else()
+  file(GLOB _respath "${_prefix}lib/clang/*")
+
+  set(CMAKE_ASM_COMPILER "${_clang_exe}" "-resource-dir=${_respath}")
+  set(CMAKE_C_COMPILER "${_clang_exe}" "-resource-dir=${_respath}")
+  set(CMAKE_CXX_COMPILER "${_clangp_exe}" "-resource-dir=${_respath}")
+endif()
+
+set(CMAKE_RC_COMPILER "${_llvm_rc}") 
+set(CMAKE_LINKER "${_ld_linker}")
+
+unset(_clang_path)
+unset(_prefix)
+unset(_clang_exe)
+unset(_clangp_exe)
+unset(_llvm_rc)
+unset(_ld_linker)
+
+set(CMAKE_C_COMPILER_TARGET ${CMAKE_SYSTEM_PROCESSOR}-w64-mingw32)
+set(CMAKE_CXX_COMPILER_TARGET ${CMAKE_C_COMPILER_TARGET})
+set(CMAKE_ASM_COMPILER_TARGET ${CMAKE_C_COMPILER_TARGET})
+
+set(CMAKE_CXX_FLAGS_INIT "-stdlib=libc++")
+
+if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.29")
+  string(TOUPPER ${_linker} CMAKE_LINKER_TYPE)
+  set(_linker)
+else()
+  set(_linker " -fuse-ld=${_linker}")
+endif()
+
+set(CMAKE_EXE_LINKER_FLAGS_INIT "--start-no-unused-arguments -stdlib=libc++ -rtlib=compiler-rt -unwindlib=libunwind --end-no-unused-arguments${_linker}")
+set(CMAKE_MODULE_LINKER_FLAGS_INIT "${CMAKE_EXE_LINKER_FLAGS_INIT}")
+set(CMAKE_SHARED_LINKER_FLAGS_INIT "${CMAKE_EXE_LINKER_FLAGS_INIT}")
+unset(_linker)

wrappers/llvm-mingw_toolchainfile_arch.cmake.in

@@ -0,0 +1,3 @@
+set(CMAKE_SYSTEM_PROCESSOR @ARCH@)
+
+include("${CMAKE_CURRENT_LIST_DIR}/llvm-mingw_toolchainfile.cmake")

wrappers/llvm-mingw_toolchainfile_arch_uwp.cmake.in

@@ -0,0 +1,15 @@
+# WindowsStore an UWP app - doesn't seem to have any effect outside of Visual Studio generators
+# https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html#cross-compiling-for-windows-10-universal-applications
+set(CMAKE_SYSTEM_NAME WindowsStore)
+set(CMAKE_SYSTEM_VERSION 10)
+set(CMAKE_SYSTEM_PROCESSOR @ARCH@)
+
+include("${CMAKE_CURRENT_LIST_DIR}/llvm-mingw_toolchainfile.cmake")
+
+set(CMAKE_C_FLAGS_INIT "-D_WIN32_WINNT=0x0A00 -DWINVER=0x0A00 -DWINAPI_FAMILY=WINAPI_FAMILY_APP -DUNICODE -D_UCRT")
+set(CMAKE_CXX_FLAGS_INIT "${CMAKE_CXX_FLAGS_INIT} ${CMAKE_C_FLAGS_INIT}")
+set(CMAKE_ASM_FLAGS_INIT "${CMAKE_C_FLAGS_INIT}")
+
+# Cant extend the content written in CMake's Modules/Platform/Windows-GNU.cmake. Replace it
+set(CMAKE_C_STANDARD_LIBRARIES "-lwindowsapp -lucrtapp -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32 -ladvapi32" CACHE STRING "Libraries linked by default with all C applications" FORCE)
+set(CMAKE_CXX_STANDARD_LIBRARIES "-lwindowsapp -lucrtapp -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32 -ladvapi32" CACHE STRING "Libraries linked by default with all C++ applications" FORCE)