CONFIGURE_PACKAGE_CONFIG_FILE(): improve generated comments

CONFIGURE_PACKAGE_CONFIG_FILE() now additionally generates
"Any changes to this file will be overwritten by the next CMake run
The input file was FooConfig.cmake.in"
into the configured file.

Alex

Modules/CMakePackageConfigHelpers.cmake

@@ -188,8 +188,13 @@ function(CONFIGURE_PACKAGE_CONFIG_FILE _inputFile _outputFile)
     endif()
   endforeach()
 
+  get_filename_component(inputFileName "${_inputFile}" NAME)
+
   set(PACKAGE_INIT "
 ####### Expanded from @PACKAGE_INIT@ by configure_package_config_file() #######
+####### Any changes to this file will be overwritten by the next CMake run ####
+####### The input file was ${inputFileName}                            ########
+
 get_filename_component(PACKAGE_PREFIX_DIR \"\${CMAKE_CURRENT_LIST_DIR}/${PACKAGE_RELATIVE_PATH}\" ABSOLUTE)
 ")