make clean doesn't run in gdbserver/common

[Joel Brobecker]

Pedro,

> > gdb/gdbserver/
> > 
> > 	* Makefile.in (CLEANDIRS, REQUIRED_SUBDIRS): New variable.
> > 	(subdir_do): New make target.  Copied from gdb/Makefile.
> > 	(maintainer-clean, realclean, distclean, clean): Call corresponding
> > 	make targets in common/Makefile.
> 
> This patch looks OK to me. I tend to defer to Pedro for gdbserver/
> changes, though, so can you give him a few (business) days to answer,
> to see if he has any concerns?

I ended up applying this patch now as an emergency measure, because
another patch which I approved but depended on this one got
inadvertantly checked in. I figured that, since both patches
looked OK, it's easier to put them both in rather than do a temp
revert of the second one.

If you have any concern with this patch, let us know, and I will
take care of reverting them both immediately.

-- 
Joel