proposed symbol format deprecations

[Tom Tromey]

Tristan> [ bfd for HP/PA is able to be cross-built ]

Thanks for the hint.

Tristan> You should talk with the HP/PA GCC maintainer, as AFAIK only
Tristan> gdb is able to debug gcc-generated binaries.

He replied off-list to say that this is what he uses for all his GCC
hacking.

He's going to test some patches for me.
I have a patch to make it possible to build somread.c anywhere the BFD
target is enabled, so that's a start.

So, consider this one dropped from the deprecation list.
I'd still like to deprecate mdebugread.c though.

Tom