MacOS: validate fails on \u

Running validate on MacOS fails with this error (due to -Werror):

libraries/Cabal/Cabal/Distribution/Simple/BuildTarget.hs:392:24:
     error: \u used with no following hex digits; treating as '\' followed by identifier [-Werror,-Wunicode]
matchBuildTarget pkg = \utarget fexists ->
                       ^
1 error generated.
make[1]: *** [utils/ghc-cabal/dist/build/tmp/ghc-cabal] Error 1

I am using ghc from homebrew to bootstrap on OS X 10.10.3.

Trac metadata

Trac field	Value
Version	7.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Build System
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