w32: Synchronous spawning gpg-agent/dirmngr/keyboxd.
* common/asshelp.h [HAVE_W32_SYSTEM] (w32_ack_to_frontend): New. * common/asshelp.c [HAVE_W32_SYSTEM] (start_new_service): Use GPGRT_PROCESS_STDOUT_PIPE flag, and read from the pipe to wait. (w32_ack_to_frontend): New. * agent/gpg-agent.c [HAVE_W32_SYSTEM] (main): Add w32_ack_to_frontend. * dirmngr/dirmngr.c [HAVE_W32_SYSTEM] (main): Likewise. * kbx/keyboxd.c [HAVE_W32_SYSTEM] (main): Likewise.
- GnuPG-bug-id: T7720
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>