I just tried to compile a project relying on the windows API, in particular "VirtualProtect", therefore the function gets declared with a "windows.h" header. Nim went trough, but gcc stopped because of a missing "Kernel32". Indeed, the C intermediate contains an #include "Kernel32" ( I'd expect a "Kernel32.h" , but there is no such extension). So, where do I get the file from or should "windows.h" be avoided?