Allow building symbol dumping without STABS support

We're building this code on Android now, and the NDK doesn't have any of the
STABS headers. It'd be easier to just skip STABS support. I thought about adding
a --disable-stabs configure argument, but I wasn't sure it was particularly
useful.

[Lei Zhang (chromium)]

Mark may have an opinion on whether we want to have --disable-stabs. In which
case, we'd probably need to muck with the makefiles and disable some unit tests
too.

[Mark Mentovai]

I don’t really care if there’s a configure argument for this. If anyone ever
needs it, they can add it. LGTM.