missing race condition, prerequesties might not be built yet.
--- a/Makefile
+++ b/Makefile
@@ -43,8 +43,8 @@
 
 session.o: session.h
 
-extras/a4-keycodes: extras/a4-keycodes.c
-	$(CC) $(CFLAGS) $(CPPFLAGS) $? $(LDFLAGS) $(uni_obj) $(termkey_obj) $(tickit_obj) -o $@
+extras/a4-keycodes: extras/a4-keycodes.c $(uni_obj) $(termkey_obj) $(tickit_obj)
+	$(CC) $(CFLAGS) $(CPPFLAGS) extras/a4-keycodes.c $(LDFLAGS) $(uni_obj) $(termkey_obj) $(tickit_obj) -o $@
 
 debug: clean
 	@$(MAKE) CFLAGS='$(CFLAGS) $(DEBUG)' a4
