[3/17] clean up allocate of BFD filenames

[Joel Brobecker]

> Currently BFD filename allocation is kind of a mess.  Generally they are
> xmalloc'd, but sometimes they are not.
> 
> This patch tries to clean it up by adding a new function that
> reallocates the filename on the BFD's obstack.  This synchronizes the
> lifetime nicely and means we don't have to separately decide when to
> free the filename.

I only skimmed through the patch, but I like the idea of it. Nice!

-- 
Joel