--- a/main.c
+++ b/main.c
@@ -45,11 +45,11 @@ extern VOID f_exit();
 
 #ifdef KR_headers
 extern VOID f_init(), sig_die();
-extern int MAIN__();
+extern int MAIN__() __attribute__((weak));
 #define Int /* int */
 #else
 extern void f_init(void), sig_die(const char*, int);
-extern int MAIN__(void);
+extern int MAIN__(void) __attribute__((weak));
 #define Int int
 #endif