environment: add the build-tools libdir to LD_LIBRARY_PATH
environment: add the build-tools libdir to LD_LIBRARY_PATH

Otherwise build tools like orcc cannot find their shared library.

fluendo/cerbero,atsushieno/cerbero,fluendo/cerbero,nirbheek/cerbero,nirbheek/cerbero,atsushieno/cerbero,fluendo/cerbero,nirbheek/cerbero,atsushieno/cerbero,GStreamer/cerbero,nirbheek/cerbero,fluendo/cerbero,fluendo/cerbero,GStreamer/cerbero,GStreamer/cerbero,atsushieno/cerbero,atsushieno/cerbero,GStreamer/cerbero,GStreamer/cerbero