Support for clang compilation (and cross-compilation) for native windows platform (--target=x86_64-windows-msvc)

[SBKarr]

Feature

Just a little fixes in cmake files to make clang builds for windows successful.

Benefit

Possibility for cross-compilation for native windows target --target=x86_64-windows-msvc on other platforms. Useful for CI, automatic builds, etc

Implementation

Patch attached: 0001-Windows-clang-fixes.patch.txt

Check for clang before NOT MINGW to reuse MinGW asms, that successfully works with clang, instead of MSVC's asms. Also, clang parser failed on backslashes with spaces.

[wenyongh]

@SBKarr thanks for the patch, it seems a good enhancement, could you help submit an PR? BTW, is it better to change to:

       if (NOT MINGW)
         set (source_all ${c_source_all} ${IWASM_COMMON_DIR}/arch/invokeNative_em64.asm)
       else ()
         set (source_all ${c_source_all} ${IWASM_COMMON_DIR}/arch/invokeNative_mingw_x64.s)
         if (CMAKE_C_COMPILER_ID STREQUAL "Clang")
           set_property(SOURCE ${IWASM_COMMON_DIR}/arch/invokeNative_mingw_x64.s PROPERTY LANGUAGE C)
         endif ()
       endif ()

which sets the property of invokeNative_mingw_x64.s when it is used and the compiler is clang.

[gajanak]

If you find this issue and the change above does not work , my Solution:

1. ensure you have enabled ASM as language in cmake. Adding to your poject or enable_language(ASM)

Setting the LANGUAGE to ASM like above.

set_property(SOURCE ${IWASM_COMMON_DIR}/arch/invokeNative_mingw_x64.s PROPERTY LANGUAGE ASM)

Tested with Clang 20.1.5 cmake 4 [cmake] -- The ASM compiler identification is Clang with GNU-like command-line [cmake] -- Found assembler: clang.exe