Fix libvpx build for ARM
Issue generated from Tuleap's migration script. Originally submitted by: Gerben Meijer (infernix)
When building current master (3facadc79402727c215f51ec52ebf3a0f79b4ba3) on a raspbian rPi 2, libvpx fails to build because of a bug in the configure.sh script.
This was fixed here:
https://github.com/webmproject/libvpx/commit/5aab99f24b7763d72889ad93237cc6875bc44c49
Please consider upgrading libvpx to a release after Dec 22 2015 or applying this patch after unpacking libvpx.