Add GDB/MI syntax check to testsuite

Add GDB/MI syntax check to testsuite

[Bob Rossi]

Hi,

So, I've got a Tcl extension that can check the syntax of a GDB/MI
Output Command. I've tested it on small examples, and it seems to work.

The original goal of allowing the Tcl to walk the parse tree will not be
done with the initial patch. That task requires a lot more thought
(However, it is easy to pass this extension a string(MI Output command), 
and have it return if the MI output command is valid or invalid
syntactically.

The problem now is, trying to figure out how to build tcl into a shared
object library(in the gdb tree of course). Then how to link that into
expect.

   - Would this be OK to do?
   - Does anyone have any pointers on how to do this?

If it's not OK to make tcl into a shared library (maybe some hosts can't
do this?) than I'll have to figure out how to link the extension
statically into tcl. I think creating a "static extension" is like
creating a custom version of a tcl interpreter. So, creating a static
extension and a normal extension might be very different.

Thanks,
Bob Rossi