diff --git a/lib/roken/strerror.c b/lib/roken/strerror.c
index b5ec6918e..93afee065 100644
--- a/lib/roken/strerror.c
+++ b/lib/roken/strerror.c
@@ -38,7 +38,7 @@
 #include <errno.h>
 
 extern int sys_nerr;
-extern char *sys_errlist[];
+extern const char *const sys_errlist[];
 
 ROKEN_LIB_FUNCTION char* ROKEN_LIB_CALL
 strerror(int eno)