[RFA 00/10] Remove some cleanups from linespec.c

[Tom Tromey <tom at tromey dot com>]

This series removes many (but not all) cleanups from linespec.c.
Generally the removals are done in the normal way: replacing manual
memory management with a self-managing data structure.

I've tried to make each patch relatively small to make them simpler to
review.

In a few cases the patch required changes outside of linespec.c.

A couple of the patches (at least #2 and #10) are obvious, though of
course it doesn't hurt to read them anyhow.

Regression tested by the buildbot.  I've also built each patch in the
series locally and run it through the gdb.linespec tests, while I was
tracking down the failures described in patch #7 (though of course the
series has changed slightly since then).

Tom