* cygheap.cc (cfree_and_set): New function.

* cygheap.cc (cfree_and_set): New function.
(cygheap_user::set_name): Use cfree_and_set to reset members.
* cygheap.h (cygheap_user): Delete static members.
(cygheap_user::puserprof): New member.
(cfree_and_set): Declare.
* dcrt0.cc (almost_null): Define.
* winsup.h (almost_null): Declare.
* syscalls.cc (cfree_and_set): Remove unused variable.
* uinfo.cc (cygheap_user::homepath_env_buf): Eliminate.
(cygheap_user::homedrive_env_buf): Ditto.
(cygheap_user::userprofile_env_buf): Ditto.
(cygheap_user::ontherange): YA change to try to preserve existing HOMEPATH and
HOMEDRIVE.  Return almost_null values when variables should not actually exist.
(cygheap_user::env_logsrv): Ditto.
(cygheap_user::env_domain): Ditto.
(cygheap_user::env_userprofile): Ditto.