fixture example doesn't use memory extra

Author: mvandervoord

examples/example_2/makefile

@@ -56,7 +56,7 @@ SRC_FILES1=\
   test/test_runners/TestProductionCode2_Runner.c \
   test/test_runners/all_tests.c
 INC_DIRS=-Isrc -I$(UNITY_ROOT)/src -I$(UNITY_ROOT)/extras/fixture/src
-SYMBOLS=
+SYMBOLS=-DUNITY_FIXTURE_NO_EXTRAS
 
 all: clean default