Changes to gdb-ui.el

[Nick Roberts]

I don't think using breakpoint faces in text-mode quite works. On a basic
xterm, an enabled breakpoint (letter 'B') stands out clearly in red, but
as disabled breakpoint (letter 'b') disappears completely. I don't understand
the subtleties of faces but maybe grey60 gets 'rounded' to white on an xterm
with 8/16 colours. Also the background of the face doesn't always match the
background of the terminal (I have found particularly so for a gnome-terminal).

In X, enabled/disabled breakpoints are distinguished by colour alone, the
icons having the same shape both in the margin and in the fringe. In text
mode the breakpoint state is already distinguished by the case of the letter
(B/b) so the same colour can be used. To help it stand out from the text,
I guess this color could be red in both cases, a color which I presume is
available on many terminals.

Nick