Explicitly handle SIGPIPE

[ericpruitt]

When running mairix in a pipeline, mairix does not delete the lock file after receiving SIGPIPE, so running something like mairix --excerpt-output a:ericpruitt | less results in Database .../mairixdb appears to be locked by (pid,node,user)=(6387,sinister,ericpruitt) the next time around if less(1) was closed before mairix finished writing data the standard output.

[vandry]

This is a duplicate of rc0#21

BTW I was thinking of solving the problem not by adding handling for SIGPIPE or other signals, but by removing the need to do locking at all, which would obviate the need to explicit cleanup. For that, see rc0#25