diff --git a/Makefile b/Makefile
index 62924d7e..4bc4c810 100644
--- a/Makefile
+++ b/Makefile
@@ -200,7 +200,7 @@ endif
 
 ci-rule = ( CC=$$(which $1); if [ -n "$$CC" ]; then \
 		CC=$$(readlink -f $$CC); echo -n "probe by $2 ($$CC): " && \
-		$(MAKE) clean >$1.log 2>$1.err && $(MAKE) all check 1>$1.log 2>$1.err && echo "OK" \
+		$(MAKE) XCFLAGS="-UNDEBUG -DMDB_DEBUG=2" clean >$1.log 2>$1.err && $(MAKE) all check 1>$1.log 2>$1.err && echo "OK" \
 			|| ( echo "FAILED"; cat $1.err >&2; exit 1 ); \
 	else echo "no $2 ($1) for probe"; fi; )
 ci: