diff --git a/build-aux/configure-lib.sh b/build-aux/configure-lib.sh
index 56776653..0c0fce3f 100644
--- a/build-aux/configure-lib.sh
+++ b/build-aux/configure-lib.sh
@@ -400,6 +400,7 @@ lib/stub/sigsetmask.c
 lib/stub/sin.c
 lib/stub/sqrt.c
 lib/stub/strftime.c
+lib/stub/strsignal.c
 lib/stub/sys_siglist.c
 lib/stub/sysconf.c
 lib/stub/system.c
diff --git a/include/string.h b/include/string.h
index cb60243a..441faeda 100644
--- a/include/string.h
+++ b/include/string.h
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2017 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2017,2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -47,6 +47,7 @@ size_t strlen (char const *);
 char *strncpy (char *to, char const *from, size_t size);
 int strncmp (char const *, char const *, size_t);
 char *strrchr (char const *s, int c);
+char *strsignal (int signum);
 char *strstr (char const *haystack, char const *needle);
 char *strtok (char *new_string, char const *delimiters);
 char *strlwr (char *string);
diff --git a/lib/stub/strsignal.c b/lib/stub/strsignal.c
new file mode 100644
index 00000000..87c3f708
--- /dev/null
+++ b/lib/stub/strsignal.c
@@ -0,0 +1,34 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <mes/lib.h>
+#include <string.h>
+
+char *
+strsignal (int signum)
+{
+  static int stub = 0;
+  if (__mes_debug () && !stub)
+    eputs ("strsignal stub\n");
+  stub = 1;
+  static char buf[30] = "Unknown signal: ";
+  strcat (buf, itoa (signum));
+  return buf;
+}