rename gzip.c's decompress to de_compress. I emailed the author
of libbz back in December about this and haven't heard anything
since...
Thanks to enami tsugutomo for pointing this out.
that this is unnecessary (only permission on the file's directory is
necessary), and it has security implications (see PR #5094). There may be
other race-condition-related implications here that this change fixes, as
well.