Shameless plug (but possibly interesting), we do something similar (but using clang) to generate a coverage report for the gobject bindings for libgit2: <a href="https://git.gnome.org/browse/libgit2-glib/tree/tools/coverage.py" rel="nofollow">https://git.gnome.org/browse/libgit2-glib/tree/tools/coverag...</a>
To make this applicable to other APIs, wouldn't it be better to use the Clang API to parse the C/C++ code and get a list of functions? Writing your own parser seems prone to failure given the difficulty of C/C++ parsing.