11 - generate error on invalid script
12 - improve script code: check for failures in call_hook only once
13 - ensure_* functions: output __FILE__, __LINENO__
14 - provide ./configure script so people don't get confused
15 - VLOCK_DEBUG environment variable for verbose error messages
20 - screensavers (aalib, directfb)
21 - test impact of inlining list code