[https://github.com/nim-lang/Nim/blob/92010becbe00b338abd4d9ef1be17739be8f69b8/lib/system/inclrtl.nim#L52](https://github.com/nim-lang/Nim/blob/92010becbe00b338abd4d9ef1be17739be8f69b8/lib/system/inclrtl.nim#L52)
It is just a `when` block. Similar to `when defined(release)`, but using the
integers from the version number as conditional.
template since(version, body: untyped) {.dirty.} =
when (NimMajor, NimMinor) >= version:
body
Run
