Add a new redo-ood command.

Prints the list of existing but out-of-date targets.

redo-ood.py

@@ -0,0 +1,17 @@
+#!/usr/bin/python
+import sys, os
+
+import vars_init
+vars_init.init([])
+
+import vars, state, deps
+from log import err
+
+if len(sys.argv[1:]) != 0:
+    err('%s: no arguments expected.\n' % sys.argv[0])
+    sys.exit(1)
+
+for f in state.files():
+    if f.is_generated and f.read_stamp() != state.STAMP_MISSING:
+        if deps.isdirty(f, depth='', max_changed=vars.RUNID):
+            print f.nicename()