Fix shlib-versions for mips-linux

[Roland McGrath]

It seems to me that the ideal would be to have symbols that get defined in
multiple libraries be listed in a Versions file only once in one place.
That is, one library would be the "ABI definer" (let's say libc is) and
other libraries overriding those symbols would be bound by the same version
crapola as the ABI definer.  Off hand, I think the simplest way to do this
would be to just throw all the symbols into a single version script without
regard to library and essentially use the one version script for all
libraries.  That should work because excess symbols in a version script
file are just ignored by ld -shared.  However, it is probably fraught with
subtle perils.  Another approach would be more magic crunching to apply the
version-reassigned symbols from one map to all the others.