Minor dbxout.c changes

[Richard Kenner]

    the automated tester found:

    The new failures are:
    powerpc-eabisim gdb.sum gdb.c++/ovldbreak.exp:

Are you sure that's my change?  There are a lot of other changes in
that batch.

    I don't really understand the interaction between stabs, c++, and
    overloaded functions.  Could you look at it?

I don't understand it *at all*, but I'll see if I can see anything obvious.