glapi: glX_proto_size.py: use argparse instead of getopt

glapi: glX_proto_size.py: use argparse instead of getopt

This is roughly equivalent to the original getopt, except that it
removes the '-h' short option, which argparse reserves for
auto-generated help messages. It does retain the long option specified
by the getopt version, and changes the makefile to use that.

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>
Acked-by: Matt Turner <mattst88@gmail.com>