chore, provide conditional HAVE_MC6_DEVICES tracking up'n'running mc6-capable links

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
chore, guard pub and pubsub tests with HAVE_MC6_DEVICES conditional

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'test/conditionals' into next

* test/conditionals:
  chore, guard pub and pubsub tests with HAVE_MC6_DEVICES conditional
  chore, provide conditional HAVE_MC6_DEVICES tracking up'n'running mc6-capable links
Merge branch 'next'

* next:
  chore, guard pub and pubsub tests with HAVE_MC6_DEVICES conditional
  chore, provide conditional HAVE_MC6_DEVICES tracking up'n'running mc6-capable links
  chore, PEBKAC, after_install does not exist, move to before_script
  test, make timed out socket upon recv() non-fatal
  chore, kick unused variable wakeup_watcher from unsermon
  chore, put ip diagnostics in after install section
  chore, kick after_failure commands altogether
  chore, final attempt with after_failure script, use if-then-fi
  fix, check if test-suite.log file exists before catting it in travis build
  chore, add before_install section to travis config
  cosmetics, for clarity spell the condition at #endif correctly
  chore, remove superfluous definition of UD_NEW_API in svc_pong_la_CPPFLAGS
  minor, kick all UD_COMPAT code in svc-pong.[ch]
  minor, lose the LTX mangling in svc-pong again, decl and def ud_mondec_init() directly
  chore, PEBKAC, mention boobs.h (for unserding.c) in its SOURCES
  chore, PEBKAC, mention ud-sock.h (for unserding.c) in its SOURCES
  minor, kick unserding-dbg.h
  minor, rename unserding-nifty.h -> ud-nifty.h and add to tools' SOURCES if used
  major, clear out old unserding API at file level
  major, clear out the old (UD_COMPAT) api from unserding.h