vm/windows: Create fstab entries in suspended VM.

Cygwin initializes mounts on _every_ login via SSH and doesn't keep them
consistently like on Unix systems, that's why we need to also add fstab
entries for the bind mounts to the store and xchg shares.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/build-support/vm/windows/default.nix

@@ -23,8 +23,10 @@ let
       "net use X: '\\\\192.168.0.2\\xchg' /persistent:yes"
       "mkdir -p /nix/store"
       "mount -o bind /cygdrive/s /nix/store"
+      "echo /cygdrive/s /nix/store none bind 0 0 >> /etc/fstab"
       "mkdir -p /tmp/xchg"
       "mount -o bind /cygdrive/x /tmp/xchg"
+      "echo /cygdrive/x /tmp/xchg none bind 0 0 >> /etc/fstab"
     ];
     suspendTo = "state.gz";
   };