Use pkg-config in build process.

Remove the hard-coded compiler and linker flags and instead use the ones
that are supplied by pkg-config. This has been tested and built on Mac
OS X Mountain Lion with the homebrew versions of Python and pkgconfig.

See: http://mxcl.github.com/homebrew/ if on Mac OS X.

For Linux and other Unix-like OSes, make sure that the -dev or -devel
packages of lua and Python for your distribution is installed.
Fix unused variable warnings during compile-time.
Fix incompatible pointer type warnings.

Use lenfunc instead of inquiry in Python 2.5 and above.