dirmngr: Do not block threads in LDAP keyserver calls.
* dirmngr/ks-engine-ldap.c: Wrap some ldap calls.
The former gpgkeys_ldap module has once been ported to dirmngr but
unfortunately the dirmngr_ldap wrapper has not been used so that we
have internal LDAP calls with these problems:
- No usable timeouts.
- On non-Windows platforms a lot of extra libs and possibly even a second copy of Libgcrypt is pulled in.
- Only one threads runs at a time.
This patch mitigates the last point.
- Signed-off-by: Werner Koch <email@example.com>