[PATCH 0/7] more constification

[Tom Tromey]

This series constifies a few more things in gdb.

A few of the patches are very basic and #4 is downright trivial.

Patch #6 casts away const in a couple spots.  There's a justification
in the patch; but I also wanted to add that the casts only affect
mdebugread.c, which can't really be said to be actively maintained in
any case.

Some of these patches are part of a larger work to constify the
argument pass to gdb commands.  This longer series isn't finished yet;
but it simplifies to the work to put patches in bottom-up and mildly
improves gdb in the process.

Tom