Merge pull request #5904 from hughbe/windows-cmake

Add support for building Swift on Windows with clang-cl and MSVC

Author: hughbe

cmake/modules/AddSwift.cmake

@@ -97,17 +97,18 @@ function(_add_variant_c_compile_link_flags)
     ""
     ${ARGN})
 
-  set(result
-    ${${CFLAGS_RESULT_VAR_NAME}}
-    "-target" "${SWIFT_SDK_${CFLAGS_SDK}_ARCH_${CFLAGS_ARCH}_TRIPLE}")
+  set(result ${${CFLAGS_RESULT_VAR_NAME}})
+
+  # MSVC and clang-cl dont't understand -target.
+  if (NOT SWIFT_COMPILER_IS_MSVC_LIKE)
+     list(APPEND result "-target" "${SWIFT_SDK_${CFLAGS_SDK}_ARCH_${CFLAGS_ARCH}_TRIPLE}")
+  endif()
 
   is_darwin_based_sdk("${CFLAGS_SDK}" IS_DARWIN)
   if(IS_DARWIN)
     list(APPEND result "-isysroot" "${SWIFT_SDK_${CFLAGS_SDK}_PATH}")
-  else()
-    if(NOT "${SWIFT_SDK_${CFLAGS_SDK}_PATH}" STREQUAL "/")
-      list(APPEND result "--sysroot=${SWIFT_SDK_${CFLAGS_SDK}_PATH}")
-    endif()
+  elseif(NOT SWIFT_COMPILER_IS_MSVC_LIKE AND NOT "${SWIFT_SDK_${CFLAGS_SDK}_PATH}" STREQUAL "/")
+    list(APPEND result "--sysroot=${SWIFT_SDK_${CFLAGS_SDK}_PATH}")
   endif()
 
   if("${CFLAGS_SDK}" STREQUAL "ANDROID")