cmd/acme: window directories missing from fs

[rogpeppe]

If I run 9p ls acme, I see something like this:

----------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 ''
d-r-x------ M 0 rogpeppe rogpeppe 0 Nov  4 07:29 acme
--rw------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 cons
----------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 consctl
d---------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 draw
---w------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 editout
--r-------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 index
--rw------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 label
--r-------- M 0 rogpeppe rogpeppe 0 Nov  4 07:29 log
d-r-x------ M 0 rogpeppe rogpeppe 0 Nov  4 07:29 new

None of the window directories are present (although they can be walked to) and there's that odd empty-named file with no permissions.

[rogpeppe]

Each window directory also contains the blank file name:

% 9p ls acme/37
''
addr
body
ctl
data
editout
errors
event
rdsel
tag
wrsel
xdata