Fix recently introduced imports poisoning. (#400)

* Fix import poison introduced.

* Move export to handles, and annotate it.

chronos/handles.nim

@@ -15,7 +15,10 @@ else:
 import "."/[asyncloop, osdefs, osutils]
 import stew/results
 from nativesockets import Domain, Protocol, SockType, toInt
-export Domain, Protocol, SockType, results, osutils
+export Domain, Protocol, SockType, results
+
+when defined(windows):
+  export raiseSignal, raiseConsoleCtrlSignal
 
 const
   asyncInvalidSocket* = AsyncFD(osdefs.INVALID_SOCKET)

chronos/osutils.nim

@@ -9,7 +9,7 @@
 import stew/results
 import osdefs, oserrno
 
-export results, osdefs, oserrno
+export results
 
 when (NimMajor, NimMinor) < (1, 4):
   {.push raises: [Defect].}