properly together. xxgdb communicates with a gdb running on a pty
that it sets to -echo,-onlcr prior to forking the gdb process.
GNU readline preserves the -echo setting while libedit was undoing it
(setting the tty to a sane state and totally confusing xxgdb's parser).
this diff simply disables libedit if both readline emulation and
"stty -echo" are used/set. that is enough to make xxgdb work once
again, but (XXX) this is not how GNU readline handles stty -echo (it
does not echo anything, but editing commands like ^A,^K, etc.
still work), so the readline emulation isn't perfect.
change reviewed by christos.
c23199d5e1