* src/eval.c: Add `inhibit-debugger'.

* src/eval.c: Add `inhibit-debugger'.
(Qinhibit_debugger): New symbol.
(call_debugger): Bind it instead of Qdebug_on_error.
(maybe_call_debugger): Test Vinhibit_debugger.
(syms_of_eval): Define inhibit-debugger.
* src/xdisp.c (set_message): Don't bind Qinhibit_debug_on_message.
(syms_of_xdisp): Remove inhibit-debug-on-message.
* lisp/emacs-lisp/debug.el (debug): Don't bind debug-on-error since
inhibit-debugger is bound instead.