Improve messages when compiling for Linux/*BSD
Improve messages when compiling for Linux/*BSD

- Don't display messages when enabling PulseAudio/ALSA/D-Bus/udev
  as these become noisy in incremental builds.
- Improve warning and error messages to be more descriptive
  and consistent.

(cherry picked from commit 4c5deea83e7e4d4b9b57446e1cabd3da2e0b2b0f)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot