Log Message:
libXres: update to 1.2.1.

Standardize buildlink3.mk while here.

Changes:

Alan Coopersmith (2):
      Update README for gitlab migration
      Update configure.ac bug URL for gitlab migration

Keith Packard (2):
      Note ABI of XResQueryClientIds
      libXres 1.2.1

Ray Strode (1):
      XRes: Use _XRead instead of _XRead32 for reading pid