Implement `debug-on-message'.

This allows tracking down what piece of code is outputting stuff in
the echo area.

* eval.c (call_debugger): Make the function non-static so that we
can call it from set_message.

* xdisp.c (set_message): Implement the new variable `debug-on-message'.
(syms_of_xdisp): Defvar it and `inhibit-debug-on-message'.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 9ee9cd74b56..78c418f3051 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3076,6 +3076,7 @@ extern _Noreturn void error (const char *, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
 extern _Noreturn void verror (const char *, va_list)
   ATTRIBUTE_FORMAT_PRINTF (1, 0);
 extern Lisp_Object un_autoload (Lisp_Object);
+extern Lisp_Object call_debugger (Lisp_Object arg);
 extern void init_eval_once (void);
 extern Lisp_Object safe_call (ptrdiff_t, Lisp_Object, ...);
 extern Lisp_Object safe_call1 (Lisp_Object, Lisp_Object);