* lisp/progmodes/gdb-mi.el: Speed up initialization. Use lexical-binding.

* lisp/progmodes/gdb-mi.el: Speed up initialization.  Use lexical-binding.
Fix up docstring according to conventions.
(gdbmi-debug-mode): New var.
(gdbmi-start-with, gdbmi-same-start, gdbmi-is-number, gdbmi-bnf-init)
(gdbmi-bnf-output, gdbmi-bnf-skip-unrecognized, gdbmi-bnf-gdb-prompt)
(gdbmi-bnf-result-record, gdbmi-bnf-out-of-band-record)
(gdbmi-bnf-async-record, gdbmi-bnf-stream-record)
(gdbmi-bnf-console-stream-output, gdbmi-bnf-target-stream-output)
(gdbmi-bnf-log-stream-output, gdbmi-bnf-result-and-async-record-impl)
(gdbmi-bnf-incomplete-record-result): New functions.
(gdb-car<): Remove function.
(gdbmi-record-list): Remove variable.
(gdbmi-bnf-state, gdbmi-bnf-offset): New vars.
(gdbmi-bnf-result-state-configs): New const.
(gud-gdbmi-marker-filter): Rewrite.
(gdb-ignored-notification, gdb-thread-created, gdb-thread-exited)
(gdb-thread-selected, gdb-running, gdb-starting, gdb-stopped):
Add `token' argument.
(gdb-done, gdb-error): New functions.
(gdb-done-or-error): Add `is-complete' argument.  Change arg order.

Fixes: debbugs:10580