unregisterised build fails with: globalRegMaybe not defined for this platform

Building HEAD fails with:

make[1]: *** [rts/dist/build/Updates.o] Error 1
ghc-stage1: panic! (the 'impossible' happened)
  (GHC version 7.9.20140429 for powerpc64-unknown-linux):
        globalRegMaybe not defined for this platform

on Linux powerpc64 and x86_64 (unregisterised).

Trac metadata

Trac field	Value
Version	7.9
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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