Fix check-names.sh
diff --git a/tests/scripts/check-names.sh b/tests/scripts/check-names.sh
index a749501..6d9ab0e 100755
--- a/tests/scripts/check-names.sh
+++ b/tests/scripts/check-names.sh
@@ -26,10 +26,11 @@
 FAIL=0
 
 printf "\nExported symbols declared in header: "
-diff exported-symbols identifiers | sed -n -e 's/^< //p' > undeclared
+UNDECLARED=$(diff exported-symbols identifiers | sed -n -e 's/^< //p') > undeclared
 
 FILTERED=$( diff tests/scripts/whitelist undeclared | sed -n -e 's/^< //p')
 
+if [ "x$UNDECLARED" != "x" ]; then
 if [ "x$FILTERED" = "x" ]; then
     echo "PASS"
 else
@@ -37,6 +38,9 @@
     echo "$FILTERED"
     FAIL=1
 fi
+else
+    echo "PASS"
+fi
 
 diff macros identifiers | sed -n -e 's/< //p' > actual-macros