gdb(1), kgdb(1): Makefile framework updates for version 7.6.1

gdb(1), kgdb(1): Makefile framework updates for version 7.6.1

The updates for gdb(1) were straight-forwards and mainly consisted of
header updates although the gnu internal library is new, as well as
a new function for libiberty.  The main work was getting kgdb(1) to
work with libgdb.  As is typically, a lot of internal changes occurred
withing gdb that rendered kgdb broken (and unbuildable).  After much
angst, kgdb works with gdb 7.6.1.