Specifically, on-stack memset() might be removed, so:
* Replace memset() with px_memset()
* Add px_memset to copy_crlf()
* Add px_memset to pgp-s2k.c
Patch by Marko Kreen
Report by PVS-Studio
Backpatch through 8.4.
pgp.h used to require including mbuf.h and px.h first. Include those in
pgp.h, so that it can be used without prerequisites. Remove mbuf.h
inclusions in .c files where mbuf.h features are not used
directly. (px.h was always used.)
This warning is new in gcc 4.6 and part of -Wall. This patch cleans
up most of the noise, but there are some still warnings that are
trickier to remove.
