common,w32: Communicate with child in non-blocking mode.
* common/exechelp-w32.c (gnupg_spawn_process): Open streams in non-blocking mode if requested.
- Fixes-commit: 83811e3f1f0c615b2b63bafdb49a35a0fc198088
- Signed-off-by: Justus Winter <justus@g10code.com>