need for 1 more extra byte.

* Checking whether the to be allocated size is larger than INT_MAX,
doesn't assure that size+16 bytes for the MEMALIGN_HACK isn't larger
than INT_MAX.

* malloc might return NULL. Checking for it before using that pointer
seems like a good idea.
Patch by Herve W. H PPP O PPP W PPP aka PPP V+ffmpeg AH gmail PPP com
Original thread:
Date: Jun 29, 2006 1:21 PM
Subject: [Ffmpeg-devel] [PATCH] minor improvements to libavcodec/mem.c

Originally committed as revision 5559 to svn://svn.ffmpeg.org/ffmpeg/trunk