Patch: Implement surrogate parent for back-shell (ITS#1815)
================ Written by Hallvard B. Furuseth and placed into the public domain. This software is not subject to any license of the University of Oslo. ================ A surrogate parent is supposed to keep back-shell children from deadlocking due to resources locked by a threading parent. Implementation note: The surrogate parent closes all unused file descriptors, so it logs errors to stderr instead of via Debug() and uses relloc() instead of ch_realloc(). Also close a file descriptor leak if fork() fails in fork.c. Hallvard B. Furuseth <firstname.lastname@example.org>, May 2002.