session patch checkin

[Tom Tromey <tromey at redhat dot com>]

When I checked in my session patch I forgot that it included a patch
to gdbtk-cmds.c.  Then when I went to check that in I realized that it
required a small patch to infcmd.c, which I can't check in without
approval from one of the blanket write people.

Because reverting the Tcl part of this patch would be hard, I am
instead checking in a minimal gdbtk-cmds.c patch which will suffice,
but which will disable the ability to save inferior command line
arguments.

I'll shepherd the final part of the patch through the gdb approval
process (even once I'm off the project).  Bleah.

Tom