Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

- Use gdb-* glob instead of gdb-6.1.1, to simplify future imports.
- Add a few entries for additional files from later gdb releases that
should also be ignored.

Update for PowerPC support. We need to keep rs6000 related files.

Update to match the GDB 6.1.1 import.

Document import of gdb-5.2.1.

Change "*coff*" to "coff*" so that the pattern will not dike out xcoffsolib.h.
I'll revisit the pattern on the next import.

Update for GDB 5.0.

GC some unused files from gdb and add them to the exclude list for future
imports.

Add upgrade instructions to facilitate future gdb imports.