bitbake: cooker: Improve inotify overflow handling

Add a proper function for clearing the mtime cache. Clean up the inotify
event overflow case to err on the side of caution and clear any potentially
now out of sync caches.

(Bitbake rev: ec60459fe2ba16966544eebff43b061abb7ed3ba)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/parse/__init__.py

@@ -84,6 +84,10 @@ def update_cache(f):
         logger.debug(1, "Updating mtime cache for %s" % f)
         update_mtime(f)
 
+def clear_cache():
+    global __mtime_cache
+    __mtime_cache = {}
+
 def mark_dependency(d, f):
     if f.startswith('./'):
         f = "%s/%s" % (os.getcwd(), f[2:])