working toolchain

# toolchain-clang-cl-xwin.cmake
cmake_minimum_required(VERSION 3.20)

set(CMAKE_SYSTEM_NAME Windows)
set(CMAKE_SYSTEM_PROCESSOR x86_64)
set(CMAKE_LINKER lld-link)


# Path to your extracted xwin sysroot
set(XWIN_ROOT "/home/user/.xwin")

# Use clang-cl, but force Windows target triple
set(CMAKE_C_COMPILER   clang-cl)
set(CMAKE_CXX_COMPILER clang-cl)

# Target triple
set(TARGET_TRIPLE x86_64-pc-windows-msvc)

# Base flags (note: space-separated, not semicolon!)
set(COMMON_INCLUDE_FLAGS
    "/imsvc${XWIN_ROOT}/crt/include "
    "/imsvc${XWIN_ROOT}/sdk/include/ucrt "
    "/imsvc${XWIN_ROOT}/sdk/include/um "
    "/imsvc${XWIN_ROOT}/sdk/include/shared "
    "/imsvc${XWIN_ROOT}/sdk/include/winrt"
)

string(REPLACE ";" " " COMMON_INCLUDE_FLAGS "${COMMON_INCLUDE_FLAGS}")

set(CMAKE_C_FLAGS_INIT   "--target=${TARGET_TRIPLE} -fuse-ld=lld ${COMMON_INCLUDE_FLAGS} /D_HAS_EXCEPTIONS=0")
set(CMAKE_CXX_FLAGS_INIT "--target=${TARGET_TRIPLE} -fuse-ld=lld ${COMMON_INCLUDE_FLAGS} /D_HAS_EXCEPTIONS=0")

set(CMAKE_C_FLAGS_DEBUG   "/MD /Zi /Od" CACHE STRING "" FORCE)
set(CMAKE_CXX_FLAGS_DEBUG "/MD /Zi /Od" CACHE STRING "" FORCE)


# Don’t let CMake inject /MDd (msvcrtd)
set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreadedDLL")

# Linker flags (for MSVC-style linker)
set(CMAKE_EXE_LINKER_FLAGS_INIT
    "/libpath:${XWIN_ROOT}/crt/lib/x86_64 \
     /libpath:${XWIN_ROOT}/sdk/lib/ucrt/x86_64 \
     /libpath:${XWIN_ROOT}/sdk/lib/um/x86_64"
)


# Avoid picking host libs
set(CMAKE_FIND_ROOT_PATH ${XWIN_ROOT})
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)