(1) patch-gdb_bsd_kvm.c
   Fix NSIG undeclared problem for NetBSD/5.2

(2) Add 'make test' results onto TODO for following:
  - NetBSD/amd64 6.1 (with 7.5.1) (with patch-gdb_bsd-kvm.c)
  - NetBSD/amd64 6.1 (with 7.5.1) (with new (5.2 adaptation) patch-gdb_bsd-kvm.c)
  - NetBSD/i386 5.2  (with 7.5.1) (ditto)
Integrate some patches from devel/libffi.
Fix building against wip's Mesa packages - otherwise pkg_install complains
when checking for dependencies

"works for me"