lint fixes:
1. avoid typedef re-definitions (perhaps introduce c11 mode for lint)
2. add __lint__ wherever __GNUC__ is defined.

merge mesa 19.1.7 into MesaLib.old.

initial import of Mesa 19.1.7 into MesaLib.old.

import the existing Mesa 10.x sources as MesaLib.old while we
handle the upgrade to Mesa 18.x.