New GDB Commander

[Dave Camp <campd oit edu>]

Hello debugger fans,

I have been working lately on a new backend for GDF using recent cvs 
gdb.  I am about to check this work in to cvs, under the name gdf-gdb.  

Some notes:

Building/Installing
-------------------
This package needs a recent checkout of gdb in its source tree.  The
prepare-tree.sh script in the toplevel directory will check out gdb
from the sourceware cvs server in the proper directory and set it up
for use in gdf-gdb.  

You must pass the --enable-build-warnings=-DUI_OUT to autogen.sh in
the gdf-gdb directory, this will turn on UI_OUT in gdb.  

Right now, gdb is just in the SUBDIRS section of
gdf-gdb/gdb/Makefile.am, so make install will go through gdb
as well as gdf-gdb.  This is less than optimal, see the TODO section
later in this email.

Running
-------
By default, Dryad will still use the libdryad commander.  To try out
gdf-gdb, set the GDF_BACKEND_NAME environment variable to
"gdf_gdb_commander"  using your favorite shell command.  

TODO/issues
-----------
* GDB should not be installed when you make install in the gdf-gdb
  directory.  Is there some sort of easy-to-do noinst_SUBDIRS?  If
  not, we need to figure out how to do this.

* Ideally, we shouldn't have to include gdb in our source tree.  This
  will require somewhat significant changes to gdb, and may or may not
  be possible in the short term.

* This has *not* started to UI_OUT.  There are hooks that recieve
  UI_OUT stuff, but they aren't used.  Everything that can be moved to
  UI_OUT should be, but UI_OUT is currently not anywhere near done.

* There are all sorts of FIXMEs in the code.  Most of them refer to
  exception handling; I'll be fixing up the exception handling
  sometime soon.  One or two are related to other issues, like for
  example the register printing support is barely working.

* Obviously, it needs to do more than it does.

In conclusion, it has some major issues and needs a lot of work, but
it sure beats libdryad :).  Play with it if you're interested, comment
on it, and we'll see how it works out.

Cheers,
-dave