The GLib dependency has been removed. The only libraries it requires to build now is jpeglib (for obvious reasons), popt (to parse command line arguments).
I have now managed to cross-compile it for Windows (using the MinGW branch of GCC). I had to tweak popt to get it to build. If it gives me trouble I will remove the popt dependency as well.
To the right here you can see a thumbnail that has been generated with the new gfxindex.