[PATCH 0/7] Fix invalid left shift of negative value.

[DJ Delorie]

-  return ((size + (1 << align) - 1) & (-1 << align));
+  return ((size + (1 << align) - 1) & -(1 << align));

This is an annoying new rule to remember.  Would this be a valid substitution?

   return ((size + (1 << align) - 1) & (~0 << align));

In cases where we're forming bitmasks, a mathematical negation doesn't
"fit" as well as logical operations.