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, 1 deletions

diff --git a/src/eval.c b/src/eval.c
index 1015b013a26..4f0d6c69a51 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -191,7 +191,7 @@ restore_stack_limits (Lisp_Object data)
 
 /* Call the Lisp debugger, giving it argument ARG.  */
 
-static Lisp_Object
+Lisp_Object
 call_debugger (Lisp_Object arg)
 {
   bool debug_while_redisplaying;