attributes: disable flatten on llvm/clang
wtv: fix variable sign in format
ansi: fix possible use of uninitialized variables
rtmpproto: Reorder conditions to help dead code elimination

This makes sure that these branches are eliminated properly
with clang with optimizations disabled.
build: Remove redundant OBJS declaration intended for programs
x86: hpeldsp: Use PAVGB instruction macro where necessary

Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Diego Biurrun <diego@biurrun.de>