Imported Upstream version 2.4.1
Merge tag 'upstream/2.4.1'

Upstream version 2.4.1
drop patches included upstream
disable altivec on powerpc
cherry-pick patch to ease debugging of test failures
correct README.Debian; the build-failure on i386 with -fPIC is due to gcc 4.9
add Breaks and Replaces on old ffmpeg packages to qt-faststart
disable optimizations on mips(el)
don't enable libbs2b on arm64, because it is not (yet) available there
disable assembler optimizations on ppc64el to (hopefully) fix the tests
prepare for upload to unstable