chore, bring travis ci file up to speed, update the repos beforehand

Signed-off-by: Sebastian Freundt <freundt@fresse.org>
Merge remote-tracking branch 'rudi/fixes'

* rudi/fixes:
  build, fix quotes in AX_ZONEINFO_RIGHT
Merge branch 'next'

* next:
  chore, bring travis ci file up to speed, update the repos beforehand
build, don't overwrite autogenerated DEPENDENCIES
build, dist-hook builds libltdl only if needed

Now "make dist" builds libtdl only if libltdlc.la does not exist, never
rebuilding it. But at least we do it only if needed and it works
correctly in parallel.