luuid -- UUID generation for Lua

This version of luuid has been extended to build successfully on
Windows systems.  It has been tested with gcc 3.4.2 under MingW on
Windows XP SP2 and Lua 5.1.2 from LuaBinaries. It should also build
with either VC6, VC7, or VC8 with appropriate tweaking of the Makefile
although that has not been explicitly tested.

The principle changes are an implementation of the small number of
functions out of libuuid.so that are actually used by the Lua
wrappers. These functions were implemented in terms of their closest
equivilents in the Win32 RPC API. The exception is uuid_time(), which
is implemented to return -1 for any UUID, with the effect that the Lua
function uuid.time(s) returns -1 for a valid UUID and nothing at all
for an invalid UUID. The emulation of libuuid is contained in wuuid.c
and wuuid.h, and only includes those entry points from libuuid that
are actually used by luuid.

Cosmetic changes to the Makefile collect the platform differences
together where the build configuration can be easily adjusted for
Windows or *nix. I also added a zip target that depends on the
info-zip open-source ZIP implementation because Windows platforms are
more likely to have that than tar.  I made no attempt to make the doc
target work. I assume that installation of enough pieces from the
GnuWin32 project would be sufficient, as would be Cygwin, but I have
not attempted that either. If there were more user documentation of
this library, that might be worth the effort.

See the file README and the comments in luuid.c for more information
about the original version and its usage.
