[compiler-rt][CMake] Simplify ARM VFP check

`TARGET_${arch}_CFLAGS` is expanded into `CMAKE_REQUIRED_FLAGS`, which
is implicitly added to the flags by `check_compile_definition`. We don't
need to re-expand the `TARGET_${arch}_CFLAGS` variable again.

Author: etcwilde

compiler-rt/lib/builtins/CMakeLists.txt

@@ -862,8 +862,7 @@ else ()
       message(STATUS "Performing additional configure checks with target flags: ${CMAKE_REQUIRED_FLAGS}")
       # For ARM archs, exclude any VFP builtins if VFP is not supported
       if (${arch} MATCHES "^(arm|armhf|armv7|armv7s|armv7k|armv7m|armv7em|armv8m.main|armv8.1m.main)$")
-        string(REPLACE ";" " " _TARGET_${arch}_CFLAGS "${TARGET_${arch}_CFLAGS}")
-        check_compile_definition(__ARM_FP "${CMAKE_C_FLAGS} ${_TARGET_${arch}_CFLAGS}" COMPILER_RT_HAS_${arch}_VFP)
+        check_compile_definition(__ARM_FP "${CMAKE_C_FLAGS}" COMPILER_RT_HAS_${arch}_VFP)
         if(NOT COMPILER_RT_HAS_${arch}_VFP)
           list(REMOVE_ITEM ${arch}_SOURCES ${arm_Thumb1_VFPv2_DP_SOURCES} ${arm_Thumb1_VFPv2_SP_SOURCES} ${arm_Thumb1_SjLj_EH_SOURCES})
         else()