[PATCH v2 0/8] Demangle minimal symbol names in worker threads

[Tom Tromey]

This is v2 of my patch series to demangle minimal symbol names in
worker threads.

v1 was here:

    https://sourceware.org/ml/gdb-patches/2019-03/msg00211.html

I think this version addresses all the comments, in particular it adds
a simple way to disable threading, and adds some configury.

Regression tested by the buildbot.  At one point this was failing most
tests on the i686 builder, but I couldn't reproduce this with my own
i686 build (on the GCC compile farm), and various checks involving
running parts of the test suite on the buildbot using valgrind did not
show anything.  In the end, the problem seems to have gone away
(though there are many gdb.arch failures on i686 -- assertion failures
in libopcodes).  So, I'm not totally sure what to make of this.

Tom