gzip -d would fail with a CRC error...

gzip -d would fail with a CRC error...

...for some inputs, and some memcpy implementations.  It is possible
that an offending input has to be compressed "from FAT filesystem
(MS-DOS, OS/2, NT)", since the sole reproducer no longer evokes a
CRC error when uncompressed and recompressed on a GNU/Linux system.
Also, using an unpatched reverse-memcpy-gzip on over 100,000 inputs
on a GNU/Linux system did not turn up another reproducer.
* inflate.c (inflate_codes): Don't call memcpy with overlapping regions.
Properly detect when source and destination overlap.
* tests/memcpy-abuse: New test, to trigger misbehavior.
* Makefile.am (TESTS): Add it.
* NEWS (Bug fixes): Mention it.
Reported by Alain Magloire in
http://thread.gmane.org/gmane.comp.gnu.gzip.bugs/307