Fix Xcode recompiling every time builds happen if a target mixes multiple languages

CMake/cotire.cmake

@@ -859,6 +859,9 @@ macro (cotire_set_cmd_to_prologue _cmdVar)
 		list (APPEND ${_cmdVar} "--warn-uninitialized")
 	endif()
 	list (APPEND ${_cmdVar} "-DCOTIRE_BUILD_TYPE:STRING=$<CONFIGURATION>")
+	if (XCODE)
+		list (APPEND ${_cmdVar} "-DXCODE:BOOL=TRUE")
+	endif()
 	if (COTIRE_VERBOSE)
 		list (APPEND ${_cmdVar} "-DCOTIRE_VERBOSE:BOOL=ON")
 	elseif("${CMAKE_GENERATOR}" MATCHES "Makefiles")