Comment 14 for bug 1790855

Yeah I formerly checked only libgps.h, but the list is somewhat bigger but still seems manageable:

API:
7.0 - add gps_fix_t.ecef (February 2018) [3]
      changed prototype of gps_read() to add buffer parameters [1]
      increased length of devconfig_t.subtype [2]
      add gnssid:svid:sigid to satellite_t [4][5]
      add mtime to attitude_t [6]

[1]: https://git.savannah.gnu.org/cgit/gpsd.git/commit/?id=6bba8b329fc7687b15863d30471d5af402467802
[2]: https://git.savannah.gnu.org/cgit/gpsd.git/commit/?id=52aab46cc0c3dca4bcd33d8b1c5e0eb11749ced6
[3]: https://git.savannah.gnu.org/cgit/gpsd.git/commit/?id=9f6d73c779168a6ec276b02a3d08ece8bfc15d51
[4]: https://git.savannah.gnu.org/cgit/gpsd.git/commit/?id=49748a4a8dc2709ec1a3c11ca62d1a2e7d49e733
[5]: https://git.savannah.gnu.org/cgit/gpsd.git/commit/?id=77c19c5f519616f6b82fc7e6d64d918a785f9ba4
[6]: https://git.savannah.gnu.org/cgit/gpsd.git/commit/?id=0220c30ee51a2a776b45564b3eeb0a8a5dc2aaaf

I agree there are non encouraging comments in [3], but this is only extra data no need to use (yet) it in consuming projects.
[2] seems to only need a recompile, but no changes.
[6] needs a rebuild for the struct change, but nothing else as the new field is unused for now.
Finally the complexity of adapting to [4][5] depends on the usage of PRN which might not be used in all projects - those two feel the hardest to me atm.

@Seth - it is the "best tool for the job", because it is the only one that feeds HW time data into chrony.