Got the tests running

test/Makefile

@@ -17,6 +17,7 @@ DEFINES =  -D UNITY_OUTPUT_CHAR=putcharSpy
 DEFINES += -D UNITY_OUTPUT_CHAR_HEADER_DECLARATION=putcharSpy\(int\)
 DEFINES += -D UNITY_OUTPUT_FLUSH=flushSpy
 DEFINES += -D UNITY_OUTPUT_FLUSH_HEADER_DECLARATION=flushSpy\(void\)
+DEFINES += -D USING_FLUSH_SPY
 DEFINES += $(UNITY_SUPPORT_64) $(UNITY_INCLUDE_DOUBLE)
 UNITY_SUPPORT_64 = -D UNITY_SUPPORT_64
 UNITY_INCLUDE_DOUBLE = -D UNITY_INCLUDE_DOUBLE

test/tests/testunity.c

@@ -3357,13 +3357,17 @@ void testFailureCountIncrementsAndIsReturnedAtEnd(void)
     UNITY_UINT savedFailures = Unity.TestFailures;
     Unity.CurrentTestFailed = 1;
     startPutcharSpy(); // Suppress output
+#ifdef USING_FLUSH_SPY
     startFlushSpy();
     TEST_ASSERT_EQUAL(0, getFlushSpyCalls());
+#endif
     UnityConcludeTest();
     endPutcharSpy();
     TEST_ASSERT_EQUAL(savedFailures + 1, Unity.TestFailures);
+#ifdef USING_FLUSH_SPY
     TEST_ASSERT_EQUAL(1, getFlushSpyCalls());
     endFlushSpy();
+#endif
 
     startPutcharSpy(); // Suppress output
     int failures = UnityEnd();