only enable auto building ffmpeg if we are not cross compiling
[rpi] setup-sdk.sh: allow overriding of buildroot and xbmc install paths
also don't require root if not needed
sq to configure - fixup after upstream rebase
[configure] use pkg-config for pulse audio detection
allows to check for minimum required version
add ffmpeg makefile for rpi
sq to configure - unset PKG_CONFIG_SYSROOT_DIR when getting FFMPEG_LIBDIR