sd: remove recursion
pulse: move helper library back to audio_outout/
access_output_udp: avoid genmf
lua: avoid genmf
misc: avoid genmf in some simple cases

Also do not hard-code -lm for the fingerprinter.
projectM: avoid genmf

Also do not define unused PROJECTM2_(CFLAGS|LIBS) substitutions.
modules: link to pthread only when needed