symbols. In disable_execute(), compute the length of the new envp
and allocate it once instead of reallocating on demand. Also append
old value of LD_PRELOAD (if any) to the new value.
use by sesh.c. This fixes NOEXEC when SELinux is used. Instead
of disabling exec in exec_setup(), disable it immediately before
executing the command. Adapted from a diff by Arno Schuring.
