build: make SWIFT_CLANG_LOCATION take precedence

If this is defined, prefer this compiler over the just built compiler.

Author: compnerd

cmake/modules/Libdispatch.cmake

@@ -8,15 +8,14 @@ if(NOT CMAKE_SYSTEM_NAME STREQUAL "Darwin")
     set(SWIFT_LIBDISPATCH_CXX_COMPILER ${CMAKE_CXX_COMPILER})
   elseif(CMAKE_SYSTEM_NAME STREQUAL CMAKE_HOST_SYSTEM_NAME)
     if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
-      if(CMAKE_SYSTEM_PROCESSOR STREQUAL CMAKE_HOST_SYSTEM_PROCESSOR AND
-        TARGET clang)
+      if(DEFINED SWIFT_CLANG_LOCATION)
+        set(SWIFT_LIBDISPATCH_C_COMPILER ${SWIFT_CLANG_LOCATION}/clang-cl${CMAKE_EXECUTABLE_SUFFIX})
+        set(SWIFT_LIBDISPATCH_CXX_COMPILER ${SWIFT_CLANG_LOCATION}/clang-cl${CMAKE_EXECUTABLE_SUFFIX})
+      elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL CMAKE_HOST_SYSTEM_PROCESSOR AND TARGET clang)
         set(SWIFT_LIBDISPATCH_C_COMPILER
           $<TARGET_FILE_DIR:clang>/clang-cl${CMAKE_EXECUTABLE_SUFFIX})
         set(SWIFT_LIBDISPATCH_CXX_COMPILER
           $<TARGET_FILE_DIR:clang>/clang-cl${CMAKE_EXECUTABLE_SUFFIX})
-      elseif(DEFINED SWIFT_CLANG_LOCATION)
-        set(SWIFT_LIBDISPATCH_C_COMPILER ${SWIFT_CLANG_LOCATION}/clang-cl${CMAKE_EXECUTABLE_SUFFIX})
-        set(SWIFT_LIBDISPATCH_CXX_COMPILER ${SWIFT_CLANG_LOCATION}/clang-cl${CMAKE_EXECUTABLE_SUFFIX})
       else()
         set(SWIFT_LIBDISPATCH_C_COMPILER clang-cl${CMAKE_EXECUTABLE_SUFFIX})
         set(SWIFT_LIBDISPATCH_CXX_COMPILER clang-cl${CMAKE_EXECUTABLE_SUFFIX})