enabled libsoxr in configure.in with --enable-ffmpeg-libsoxr
added lib/libsoxr
xbmc adjustments for ffmpeg master head, rev 31f386c, 2013-05-29
added -m32 compile flag for 32-bit libsoxr
also make libsoxr during ffmpeg make phase
XBMC.xcodeproj: Enable OpenMP Support=Yes, Library Search Paths += lib/libsoxr, Other Linker Flags += -lsoxr