* src/gpg-error.h.in (GPGRT_SPAWN_KEEP_STDIN): New.
(GPGRT_SPAWN_KEEP_STDOUT, GPGRT_SPAWN_KEEP_STDERR): New.
* src/gpgrt-int.h: Add comment.
* src/spawn-posix.c (do_exec): Add the argument FLAGS.
(_gpgrt_spawn_process): Add FLAGS.
(_gpgrt_spawn_process_fd): Follow the change.
(_gpgrt_spawn_process_detached): Likewise.
* src/spawn-w32.c (_gpgrt_spawn_process): Handle FLAGS.