diff --git a/src/modules/_Stdio/Makefile.in b/src/modules/_Stdio/Makefile.in
index 998795672c96985c123e49c0280da2f46a677277..459d57863d749267379d3b3a164d335a6dd156d9 100644
--- a/src/modules/_Stdio/Makefile.in
+++ b/src/modules/_Stdio/Makefile.in
@@ -9,6 +9,8 @@ CONFIG_HEADERS=@CONFIG_HEADERS@
 
 @static_module_makefile@
 
+buffer.o: $(SRCDIR)/buffer.c
+
 local_tests:
 	$(RUNPIKE) $(SRCDIR)/socktest.pike