Backout 6f5b253ab7b7 - Bug 818843 - This change broke building B2G on the mac. r=me

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extra : rebase_source : 73c82280ee691d4874e0c51c5e90165e92cc40f0
Backout c9831bed6bb7 - Bug 818843 - This change broke building B2G on the mac. r=me

--HG--
extra : rebase_source : 7bef8dc1c394d45302f17379ab2cbd90ecda6975