Fix and change to .app for gitignore.

tests/000-default/run.sh

@@ -5,7 +5,7 @@ CC_FLAGS="-O2"
 
 OWN=$(dirname $(realpath $0))
 TEST_SOURCE=$OWN/testing.c
-TEST_OUTPUT=$OWN/testing
+TEST_OUTPUT=$OWN/testing.app
 HEADERS=$OWN/../../headers/cx
 LIBRARY=$OWN/../../build-generic
 LIBRARY_MAKE=$OWN/../../build-generic/make.sh