mbelib: 1.2.5 - mbelib, P25 Phase 1 and ProVoice vocoder

Updated to use *std_cmake_args and stop removal and then immediate
rebuild of build dir.

This lib is Needed to compile DSD which will be the subject of a
future pull request.

See:
https://github.com/szechyjs/mbelib
https://github.com/szechyjs/dsd