doc/faq: mention concat protocol documentation in the protocol concatenation entry
doc/faq: fill missing word in the concat protocol entry
lavf/img2dec: fix option help fields
lavf/img2enc: extend current options documentation
ffmpeg: fix typo in open_files() message

Found-By: Justin Ruggles
Fix compilation with --disable-everything on x86_32.

Fixes ticket #2183.
gifdec: check that w,h is not zero

Fixes out of array access

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
eacmv: Free frames on resolution changes

Fixes out of array reads

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>