getpid is a posix function that is not part of the C standard, so we can not use it to test with on Windows.

We can add a Windows equivalent of this test calling GetCurrentProcess [1], and GetProcessId [2].

[1] : https://docs.microsoft.com/en-us/windows/desktop/api/processthreadsapi/nf-processthreadsapi-getcurrentprocess
[2] : https://docs.microsoft.com/en-us/windows/desktop/api/processthreadsapi/nf-processthreadsapi-getprocessid