(ITS#8504) LDMB: Return EPIPE from mdb_env_copyfd2 instead abort on SIGPIPE

[lmb@cloudflare.com]

Full_Name: Lorenz Bauer
Version: 
OS: 
URL: https://gist.github.com/lmb/63189f83c5f00dd59c86f3c9bc07694d
Submission from: (NULL) (2606:4700:1000:8200:5530:fc35:2f95:4f31)


As per the discussion in [1] I'm providing a patch to block and handle SIGPIPE
in the copy thread used when performing a compacting copy.

The attached file is derived from OpenLDAP Software. All of the modifications to
OpenLDAP Software represented in the following patch(es) were developed by
CloudFlare, Inc. CloudFlare, Inc. has not assigned rights and/or interest in
this work to any party. I, Lorenz Bauer am authorized by CloudFlare, Inc., my
employer, to release this work under the following terms.
CloudFlare, Inc. hereby place the following modifications to OpenLDAP Software
(and only these modifications) into the public domain. Hence, these
modifications may be freely used and/or redistributed for any purpose with or
without attribution and/or other notice.

1: http://www.openldap.org/lists/openldap-technical/201609/msg00026.html