diff --git a/tests/Makefile.am b/tests/Makefile.am
index 585d0171d1..d9dbf0e157 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -99,3 +99,8 @@ checksrc:
 	cd libtest && $(MAKE) checksrc
 	cd unit && $(MAKE) checksrc
 	cd server && $(MAKE) checksrc
+
+if CURLDEBUG
+# for debug builds, we scan the sources on all regular make invokes
+all-local: checksrc
+endif