Seems all media-libs/libpostproc ebuilds have this bug: [ebuild R ] media-libs/libpostproc-10.20140517-r1 USE="pic (-altivec) -static-libs" ABI_X86="(64) -32 (-x32)" CPU_FLAGS_X86="mmx mmxext -3dnow" 0 KiB ... >>> Configuring source in /var/tmp/portage/media-libs/libpostproc-10.20140517-r1/work/libpostproc-10.20140517 ... * abi_x86_64.amd64: running multilib-minimal_abi_src_configure install prefix /usr source path /var/tmp/portage/media-libs/libpostproc-10.20140517-r1/work/libpostproc-10.20140517 C compiler x86_64-pc-linux-gnu-gcc ARCH x86 (corei7-avx) big-endian no runtime cpu detection no MMX enabled yes MMXEXT enabled yes 3DNow! enabled yes 3DNow! extended enabled yes SSE enabled yes SSSE3 enabled yes AVX enabled yes CMOV enabled yes CMOV is fast yes EBX available yes EBP available no debug symbols yes optimize for size no optimizations yes static no shared yes postprocessing support yes threading support pthreads License: GPL version 2 or later Creating config.mak and config.h... >>> Source configured. CPU_FLAGS_X86 var does not affect src_configure, because CPU_FEATURES= var is not used in src_configure function of all libpostproc ebuilds. Also list in CPU_FEATURES= is incomplete: it does not include '3dnowext sse ssse3 avx'.
After looking at bug #455814 it seems that CPU_FEATURES= list is complete, instead build system needs cleanup.
Created attachment 458148 [details] emerge-info.txt same at a tinderbox image
Created attachment 458150 [details] config.log
Created attachment 458152 [details] emerge-history.txt
Created attachment 458154 [details] environment
Created attachment 458156 [details] etc.portage.tbz2
Created attachment 458158 [details] media-libs:libpostproc-10.20140517-r1:20161231-150707.log
This has become an issue on my system a few days ago with the version bump of libav-12 which causes a rebuild of this package. There will probably be a few other folks having this issue as this package hasn't been built on my system for some time now.
Created attachment 463746 [details, diff] libpostproc-10.20140517-no-deprecated-cpu-flag.patch libav no longer defines AV_CPU_FLAG_MMX2. See http://lists.libav.org/pipermail/libav-commits/2015-August/017354.html. AFAIK, AV_CPU_FLAG_MMXEXT should provide equivalent behavior.