Log Message:
Update gnuradio-* from 3.7.5.2 to 3.7.6
GNU Radio releases 3.7.6 and 3.7.5.2 are available for download:

   ( several tens of lines omitted for URL and List of contributors)

Release 3.7.5.2 is a bug-fix only maintenance patch following 3.7.5.1,
and will be the last one for the 3.7.5 release.  Release 3.7.6
incorporates all these fixes and adds significant new features.