BFD_ASSEMBLER, bignum questions

[Stan Shebs]

A couple random GAS questions that the current sources are not
answering for me:

* Are there any non-BFD configurations still in use? It looks like
configure can generate some, but they mostly seem really obscure,
maybe they're no longer in use.

* Is the bignum code actually needed? 64-bit values seem to depend
on 64-bit BFD and do 64-bit arithmetic, so I don't see how bignum
code would ever need to kick in.

Stan