emacs-28 95a0227: Avoid exiting when outputting error messages during loadup

[Eli Zaretskii]

branch: emacs-28
commit 95a0227ff74e4863203a8c2050727e57f8172861
Author: Gregory Heytings <gregory@heytings.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Avoid exiting when outputting error messages during loadup
    
    * src/print.c (print_error_message): Don't call
    'substitute-command-keys' when it isn't fboundp.
---
 src/print.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/print.c b/src/print.c
index d4301fd..9f684bb 100644
--- a/src/print.c
+++ b/src/print.c
@@ -941,7 +941,11 @@ print_error_message (Lisp_Object data, Lisp_Object stream, 
const char *context,
   else
     {
       Lisp_Object error_conditions = Fget (errname, Qerror_conditions);
-      errmsg = call1 (Qsubstitute_command_keys, Fget (errname, 
Qerror_message));
+      errmsg = Fget (errname, Qerror_message);
+      /* During loadup 'substitute-command-keys' might not be available.  */
+      if (!NILP (Ffboundp (Qsubstitute_command_keys)))
+       errmsg = call1 (Qsubstitute_command_keys, errmsg);
+
       file_error = Fmemq (Qfile_error, error_conditions);
     }