fchmod, fchown, lchown.
* winsup/cygwin/syscalls.cc (chown_worker): Use previous
uid/gid if new uid/gid is -1.
New static function with chown functionality.
(chown): Call chown_worker with SYMLINK_FOLLOW.
(fchown): New function. Call chown_worker with SYMLINK_FOLLOW.
(lchown): New function. Call chown_worker with SYMLINK_IGNORE.
* cygwin.din: Add symbols for fchown, lchown.
* path.cc (symlink): Call `set_file_attribute()' and
`SetFileAttributeA()' instead of `chmod()' to set
uid/gid correct.
796e3b20bc