COMP: On some project configure may not copy right away

CheckCXXSourceRuns.cmake

@@ -30,7 +30,7 @@ MACRO(CHECK_CXX_SOURCE_RUNS SOURCE VAR COMMENT)
     ENDIF(CMAKE_REQUIRED_INCLUDES)
     SET(CMAKE_EMPTY_INPUT_FILE_CONTENT "${SOURCE}")
     CONFIGURE_FILE("${CMAKE_CURRENT_SOURCE_DIR}/CMakeEmptyInputFile.in"
-      "${CMAKE_BINARY_DIR}/CMakeFiles/CMakeTmp/src.cxx")
+      "${CMAKE_BINARY_DIR}/CMakeFiles/CMakeTmp/src.cxx" IMMEDIATE)
 
     MESSAGE(STATUS "Performing Test ${COMMENT}")
     TRY_RUN(${VAR} HAVE_${VAR}