* cygheap.cc (cygheap_root::cygheap_root): New function.

    * cygheap.cc (cygheap_root::cygheap_root): New function.
        (cygheap_root::~cygheap_root): Ditto.
        (cygheap_root::operator=): Ditto.
        (cygheap_user::~cygheap_user): Ditto.
        (cygheap_user::set_name): Ditto.
        (cygheap_user::set_logsrv): Ditto.
        (cygheap_user::set_domain): Ditto.
        (cygheap_user::set_sid): Ditto.
        * cygheap.h (cygheap_root): New class.
        (cygheap_user): Ditto.
        (init_cygheap): Change type of `root' member to cygheap_root.
        Add `user' member.
        * dir.cc (opendir): Use new `cygheap_root' class.
        * dcrt0.cc (dll_crt0_1): Use new `cygheap_user' class.
        * fork.cc (fork_parent): Ditto.
        * grp.cc (getgroups): Ditto.
        * passwd.cc (search_for): Ditto.
        * path.cc: Use new `cygheap_root' class throughout.
        * pinfo.h (_pinfo): Remove `use_psid'. Move `username', `psid',
        `logsrv', `domain', `orig_{uid,gid}' and `real_{uid,gid}' to
        cygheap_user class.
        * security.cc: Use new `cygheap_user' class throughout.
        * shared.cc (sec_user): Ditto.
        * sigproc.cc (proc_subproc): Remove copy statements for user
        related information moved to `cygheap_user' class.
        * spawn.cc (spawn_guts): Invalidate current chroot settings
        when creating Windows environment. Use new `cygheap_user' class.
        * syscalls.cc: Use new `cygheap_user' class throughout.
        * uinfo.cc: Ditto.
        * uinfo.cc (internal_getlogin): Change parameters to reflect the
        move of user information to cygheap.