am 3b008f36: am 83f69eb5: Prepend ccache to CC/CXX if necessary.

Merge commit '3b008f36956c35f58d510ad3da5090cf21a08349'

* commit '3b008f36956c35f58d510ad3da5090cf21a08349':
  Prepend ccache to CC/CXX if necessary.