you can use this article:
"
$(Include =filename )
$(Must_Include =filename )
The include and must_include variables specify a file that contains text that should be included in the script. The entire script can thus be put in a file. This is a a user-defined variable.
The difference between include and must_include is that include will fail silently if the file is not found during script reload, while must_include will throw an error if the file is not found.
Examples:
$(Include=abc.txt);
$(Must_Include=def.txt);
"
References:
The $(Include) which you $(Must_Include) into your toolkit
