Disable -Wgnuzero-variadic-macro-arguments for non-Windows platforms

This is due to a bug in Google Test that is causing non-Windows builds to fail.

test/StringUtils.test.cpp

@@ -131,6 +131,13 @@ TEST(String, stringFromChar)
 
 }
 
+#if defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wgnu-zero-variadic-macro-arguments"
+#elif defined(__clang__) || defined(__APPLE__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wgnu-zero-variadic-macro-arguments"
+#endif
 
 template<typename T>
 class StringFromSignedIntegerTest : public ::testing::Test
@@ -183,6 +190,13 @@ TYPED_TEST(StringFromFloatingPointTest, StringFromFloatingPointTestEdgeCases)
 	EXPECT_EQ("1.500000"s, NAS2D::stringFrom(TypeParam{1.5}));
 }
 
+#if defined(__GNUC__)
+#pragma GCC diagnostic pop
+#elif defined(__clang__) || defined(__APPLE__)
+#pragma clang diagnostic pop
+#endif
+
+
 
 TEST(String, stringToFromRoundtrip)
 {