Log Message:
(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)