diff --git a/Makefile.in b/Makefile.in
index 2d75b534c530..2658629f9183 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -24,7 +24,13 @@ endif
 include $(topsrcdir)/config/config.mk
 
 ifneq (mobile/android,$(MOZ_BUILD_APP))
-$(MDDEPDIR)/buildid.h.stub $(MDDEPDIR)/source-repo.h.stub: FORCE
+# We only want to generate buildid.h once, during the export phase.
+ifeq ($(MAKECMDGOALS),buildid.h)
+$(MDDEPDIR)/buildid.h.stub: FORCE
+endif
+ifeq ($(MAKECMDGOALS),source-repo.h)
+$(MDDEPDIR)/source-repo.h.stub: FORCE
+endif
 endif
 source-repo.h: $(MDDEPDIR)/source-repo.h.stub
 buildid.h: $(MDDEPDIR)/buildid.h.stub