Make opcodes configure depend on bfd configure

The idea is for opcodes to be able to see whether bfd is compiled
for 64-bit.  A lot of --enable-targets=all libopcodes is wasted space
if bfd can't load 64-bit target object files.

	* Makefile.def (configure-opcodes): Depend on configure-bfd.
	* Makefile.in: Regenerate.