Mouse events in the margin using an xterm

[Nick Roberts]

There are problems with mouse events in the margin using an xterm. The
bindings are set up with xt-mouse.el and a mouse event generated using
gdb-mouse-toggle-breakpoint looks like:

(left-margin (#<window 4 on myprog.c> left-margin (0 . 41) 44))

while using X it looks like:

(mouse-1 (#<window 7 on myprog.c> left-margin (7 . 84) 255102803
 nil 673 (1 . 6) nil (7 . 6) (0 . 13)))

I think the car should be mouse-1, but I don't think this is what causes
gdb-mouse-toggle-breakpoint to fail. Its to do with the number of elements in
the list and that posn-point returns left-margin and not a number.

I've also tried to use gdb-mouse-toggle-breakpoint on the console (TERM=linux)
with t-mouse.el. Here Emacs crashes with a segmentation fault in
read-key-sequence. I'll investigate this further.

Nick