Fix symlink handling, especially for symlinks not below "env_dir"

tests/cwd.t

@@ -33,5 +33,8 @@ Check that symlinked dirs get handled correctly.
   $ cd sub_linked
   ENTERED: PWD:sub_linked pwd:sub_linked from:cwd.t to:sub_linked event:enter
   $ cd sub2
-  ENTERED: PWD:sub2 pwd:sub2 from:sub_linked to:sub2 event:enter
-  $ cd .
+
+  $ cd ../..
+  LEFT: PWD:cwd.t pwd:cwd.t from:sub2 to:cwd.t event:leave
+  $ cd sub_linked/sub2
+  ENTERED: PWD:sub2 pwd:sub2 from:cwd.t to:sub2 event:enter

tests/leave.t

@@ -88,3 +88,28 @@ Test that .env is sourced only once with AUTOENV_HANDLE_LEAVE=0.
   ENTERED
   $ cd ..
   $ cd sub
+
+
+Test that "leave" is not triggered when entering an outside dir via symlink.
+
+  $ AUTOENV_HANDLE_LEAVE=1
+  $ cd ..
+  LEFT
+  $ mkdir outside
+  $ cd outside
+  $ echo 'echo ENTERED outside: PWD:${PWD:t} pwd:${${"$(pwd)"}:t} from:${autoenv_from_dir:t} to:${autoenv_to_dir:t} event:${autoenv_event}' > .env
+  $ echo 'echo LEFT outside: PWD:${PWD:t} pwd:${${"$(pwd)"}:t} from:${autoenv_from_dir:t} to:${autoenv_to_dir:t} event:${autoenv_event}' > .env.leave
+  $ test_autoenv_auth_env_files
+
+  $ cd ..
+  $ ln -s ../outside sub/symlink
+  $ cd sub
+  ENTERED
+  $ cd symlink
+  ENTERED outside: PWD:symlink pwd:symlink from:sub to:symlink event:enter
+
+  $ cd ../..
+  LEFT
+  LEFT outside: PWD:leave.t pwd:leave.t from:symlink to:leave.t event:leave
+  $ cd sub/symlink
+  ENTERED outside: PWD:symlink pwd:symlink from:leave.t to:symlink event:enter