diff --git a/src/include/86box/86box.h b/src/include/86box/86box.h
index e7f79b36f..20e5b151b 100644
--- a/src/include/86box/86box.h
+++ b/src/include/86box/86box.h
@@ -152,6 +152,7 @@ extern int	config_changed;			/* config has changed */
 /* Function prototypes. */
 #ifdef HAVE_STDARG_H
 extern void	pclog_ex(const char *fmt, va_list);
+extern void	fatal_ex(const char *fmt, va_list);
 #endif
 extern void	pclog_toggle_suppr(void);
 extern void	pclog(const char *fmt, ...);