[gdb 19981224] Enable linking gdb against shared libbfd

[Jim Blandy]

In a long-ago discussion on whether GDB should use a shared BFD, Ian
Taylor said:

> Correct: there are no current plans to use -release when building a
> BFD shared library.
>
> I believe the correct solution for BFD is to rename the shared library
> based on the BFD version number.  However, this is not currently
> implemented.

Why is including the BFD version in the shared library name preferable
to using -release?