message: Fix the catalyst build
  The target flag was only added to CXX flags and not C flags, so the bid C files
  were being built for the wrong platform.
diff: @@ -5,5 +5,6 @@ set_common_xcode_attributes()
  set(CMAKE_XCODE_ATTRIBUTE_SUPPORTED_PLATFORMS "macosx")
  set(CMAKE_XCODE_EFFECTIVE_PLATFORMS "-maccatalyst")
  set(CMAKE_XCODE_ATTRIBUTE_MACOSX_DEPLOYMENT_TARGET "10.15")
  +set(CMAKE_C_FLAGS "-target x86_64-apple-ios13.0-macabi -Wno-overriding-t-option")
  set(CMAKE_CXX_FLAGS "-target x86_64-apple-ios13.0-macabi -Wno-overriding-t-option")
  set(CPACK_SYSTEM_NAME "maccatalyst")
  