isnull.c (uuid_is_null), pack.c (uuid_pack),
parse.c (uuid_parse), unpack.c (uuid_unpack),
unparse.c (uuid_unparse), uuid.h, uuidP.h,
uuid_time.c (uuid_time, uuid_type, uuid_variant):
Use const for pointer variables that we don't modify. Add
the appropriate ifdef's in uuid.h to make it be C++ friendly.
parse.c, compare.c: Include string.h to fix gcc -Wall complaints.
gen_uuid.c: Define _SVID_SOURCE to avoid gcc -Wall errors because some
required structures wouldn't be otherwise defined. Fix a minor gcc
-Wall nit in the declaration of get_random_fd().
compare.c (uuid_compare): Change sense of uuid_compare so that its
return values match that of memcpy and the uuid_compare() found in
Paul Leach's internet-draft.