The random number generator in src/libqhull/random.c makes me suspicious.
Maybe it would be better to switch to random(3).

The include files used in user code have lots of stuff in them that
really only the library needs.  These could be split out.

Separate versions of all functions for various floating point
precisions.  Perhaps via multiple #include's.

Convert executables to getopt and --help, and stop using isatty.
