diff --git a/Modules/CMakeDetermineCompilerId.cmake b/Modules/CMakeDetermineCompilerId.cmake
index 378e46fe983..5e880761add 100644
--- a/Modules/CMakeDetermineCompilerId.cmake
+++ b/Modules/CMakeDetermineCompilerId.cmake
@@ -734,7 +734,7 @@ Id flags: ${testflags} ${CMAKE_${lang}_COMPILER_ID_FLAGS_ALWAYS}
         set(id_clang_cxx_library "CLANG_CXX_LIBRARY = \"${CMAKE_MATCH_3}\";")
       endif()
     endif()
-    if(CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_SYSROOT MATCHES "^$|[Mm][Aa][Cc][Oo][Ss]")
+    if(CMAKE_OSX_SYSROOT MATCHES "[Mm][Aa][Cc][Oo][Ss]" OR (CMAKE_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_SYSROOT STREQUAL ""))
       set(id_code_sign_identity "-")
       # When targeting macOS, use only the host architecture.
       if (_CMAKE_APPLE_ARCHS_DEFAULT)