Build entirely broken

[Simon Peyton Jones]

>From a clean build I'm getting this

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/CString.o: No such file or directory

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/Classes.o: No such file or directory

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/Debug.o: No such file or directory

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/IntWord64.o: No such file or directory

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/Magic.o: No such file or directory

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.o: No such file or directory

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/Tuple.o: No such file or directory

ld: cannot find libraries/ghc-prim/dist-install/build/GHC/Types.o: No such file or directory

And indeed those files don't exist.  In earlier builds they were there.
The command line for eg CString was

"inplace/bin/ghc-stage1" -hisuf hi -osuf  o -hcsuf hc -static  -O0 -H64m -Wall -fllvm-fill-undef-with-garbage    -Werror    -this-unit-id ghc-prim-0.5.3 -hide-all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -Ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-install/build/./autogen -Ilibraries/ghc-prim/dist-install/build/./autogen -Ilibraries/ghc-prim/.    -optP-include -optPlibraries/ghc-prim/dist-install/build/./autogen/cabal_macros.h -package-id rts -this-unit-id ghc-prim -XHaskell2010 -O -dcore-lint -dno-debug-output -ticky  -no-user-package-db -rtsopts  -Wno-trustworthy-safe -Wno-deprecated-flags     -Wnoncanonical-monad-instances  -odir libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-install/build -stubdir libraries/ghc-prim/dist-install/build -split-objs  -dynamic-too -c libraries/ghc-prim/./GHC/CString.hs -o libraries/ghc-prim/dist-install/build/GHC/CString.o -dyno libraries/ghc-prim/dist-install/build/GHC/CString.dyn_o
which looks right.
What's going on?
This has me totally stalled.
Simonb
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