Fixed epsilon for half types

test/gtc/gtc_constants.cpp

@@ -14,7 +14,9 @@ int main()
 {
 	int Error(0);
 
-    
+	float MinHalf = 0.0f;
+	while (glm::half(MinHalf) == glm::half(0.0f))
+		MinHalf += std::numeric_limits<float>::epsilon();
 
 	return Error;
 }