avconv: add infrastructure for using hwaccels
avconv: add support for VDPAU decoding
libschroedingerenc: do not assert on values from external libraries

Signed-off-by: Anton Khirnov <anton@khirnov.net>
build: more fine-grained dependencies for documentation build tools

Perl is needed to build the manual pages, texi2html for the HTML pages.
ac3dec: Fix out-of-array read

Signed-off-by: Diego Biurrun <diego@biurrun.de>
mpegaudiodec: Consistently handle fixed/float templating
Add missing #includes for *INT64_MAX and *INT64_C