Code landed after FIREFOX_52_0_2esr_RELEASE breaks Tor Browser build for Windows
Building ESR 52 with mingw-w64 at least is broken using https://hg.mozilla.org/releases/mozilla-esr52/rev/e8651b7e41c8. Doing so with https://hg.mozilla.org/releases/mozilla-esr52/rev/afa66bcf9203 (FIREFOX_52_0_2esr_RELEASE) is still fine.
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