grc: always show the label of the selected port

Suggested by Seth Hitefield
Fix handling of GR_USE_SYSTEM_LIBGSM and GR_USE_SYSTEM_LIBCODEC2
blocks: remove stray ctrlport XML definitions
Merge remote-tracking branch 'maitland/gr-vocoder-use-system-codecs' into maint
vocoder: minor cleanup in library detection
Merge branch 'maint'
trellis: fix cmake variables for compatibility
Merge remote-tracking branch 'gnuradio-wg-grc/master_grcwg'