Conditional Compilation

[HzanRsxa2959]

Add a way to perform conditional compilation: https://docs.microsoft.com/en-us/cpp/preprocessor/hash-if-hash-elif-hash-else-and-hash-endif-directives-c-cpp?view=msvc-160

I don't know how common of a case this is to warrant such a feature, but I realized the need for it here: https://forum.mixmods.com.br/f16-utilidades/t5341-cleo-property-template