Merge devo/bfd with GDB's bfd.

Merge devo/bfd with GDB's bfd.
Get getopt and obstack from -liberty rather than compiling them here.
* coffread.c: turn a printf into a complain(), and try to deal more
gracefully with botched-looking lineno pointers.
* dbxread.c:  Use bfd_get_symcount rather than bfd_get_symcount_upper_bound.
Don't coredump on files with zero symbols in them (a BFD bug showed this one).
* environ.c:  Pass GNUTARGET into the parent (gdb) as well as the child.