Add possibility to specify compile arguments

[tudortimi]

Xcelium supports usage of many arguments (probably all actually) under -makelib/-endlib blocks. This makes it possible to concatenate a full xrun args file and to compile each library with different arguments. For example, we can turn off certain warnings in one library, we can turn on certain compiler features in another library, etc.

[tudortimi]

This should be specifiable per tool. The native plugin has something similar, to configure either GCC or clang args.