It is common for C libraries to require some init call on startup, like Tk_Init. It would be nice to know about modules that need to call such functions, and hook them into julia's _init in the future when julia code is used as a library.

Currently we have 2 overall phases: definition time (when a source file is loaded) and run time. We need to insert "startup time" in between. It takes place right after load time when you first load a file, and also at startup when "compiled" code is loaded.