diff --git a/src/main.h b/src/main.h
index 3a01b49..f06d4bb 100644
--- a/src/main.h
+++ b/src/main.h
@@ -230,7 +230,10 @@ SCM_DEFINE (G_ ## c_func, zile_func,				\
 
 /* Call an interactive function. */
 #define FUNCALL(c_func)				\
-  gfuncall (G_ ## c_func)
+  ({						\
+     extern SCM G_ ## c_func ();		\
+     gfuncall (G_ ## c_func);			\
+   })
 
 /* Call an interactive function with a universal argument. */
 #define FUNCALL_ARG(c_func, uniarg)             \
@@ -330,11 +333,17 @@ SCM_DEFINE (G_ ## c_func, zile_func,				\
       cname = true;					 \
     }
 
-#define G_FUNCALL(c_func) \
-  gfuncall (G_ ## c_func)
-
-#define G_FUNCALL_ARG(c_func, uniarg) \
-  gfuncall_arg (G_ ## c_func, uniarg)
+#define G_FUNCALL(c_func)			\
+   ({						\
+      extern SCM G_ ## c_func ();		\
+      gfuncall (G_ ## c_func);			\
+    })
+
+#define G_FUNCALL_ARG(c_func, uniarg)		\
+   ({						\
+      extern SCM G_ ## c_func ();		\
+      gfuncall_arg (G_ ## c_func, uniarg);	\
+    })
 
 /*--------------------------------------------------------------------------
  * Keyboard handling.