When starting mount or umount, the environment was not cleared and
could be used for privilege escalation (CVE-2015-3202).
This is a port of the fix to full fuse by using execle(3) instead
of execl(3)
The libfuse used by OpenIndiana has the same features as libfuse-lite
though requiring some code variants. Merging them simplifies supporting
both.
Variants for OpenIndiana are selected when defining __SOLARIS__
Jean-Pierre André
szaka