hello all,

i'm getting the following error quite consistently on OSX, for getting the docs working / built

and its quite impossible to install if the docs aren't fully built

i've bolded below an except 

how do i fix thisssss please help meeeee :)

many thanks.

Extension error:
The 'ghc-flag' directive is already registered to domain std
docs/users_guide/ghc.mk:16: recipe for target 'docs/users_guide/users_guide.pdf' failed
make[1]: *** [docs/users_guide/users_guide.pdf] Error 2
make[1]: *** Waiting for unfinished jobs....

Extension error:
The 'ghc-flag' directive is already registered to domain std

Extension error:
The 'ghc-flag' directive is already registered to domain std
docs/users_guide/ghc.mk:28: recipe for target 'docs/users_guide/build-man/ghc.1' failed

the full end of the build is as follows

any 


/usr/local/bin/ginstall -c -m 755 utils/genapply/dist/build/tmp/genapply inplace/lib/bin/genapply
cp libffi/build/inst/lib/libffi.a rts/dist/build/libCffi.a
"inplace/bin/ghc-stage1" -hisuf hi -osuf  o -hcsuf hc -static  -H32m -O -Wall      -this-unit-id ghc-prim-0.5.2.0 -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 -O2  -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   -dynamic-too -c libraries/ghc-prim/./GHC/Tuple.hs -o libraries/ghc-prim/dist-install/build/GHC/Tuple.o -dyno libraries/ghc-prim/dist-install/build/GHC/Tuple.dyn_o
Running Sphinx v1.8.1
Running Sphinx v1.8.1
Running Sphinx v1.8.1
loading pickled environment... done
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 4 source files that are out of date
updating environment: 0 added, 0 changed, 0 removed
looking for now-outdated files... none found
pickling environment... done
preparing documents... done
writing output... [ 25%] index
Extension error:
The 'ghc-flag' directive is already registered to domain std
docs/users_guide/ghc.mk:16: recipe for target 'docs/users_guide/users_guide.pdf' failed
make[1]: *** [docs/users_guide/users_guide.pdf] Error 2
make[1]: *** Waiting for unfinished jobs....

Extension error:
The 'ghc-flag' directive is already registered to domain std

Extension error:
The 'ghc-flag' directive is already registered to domain std
docs/users_guide/ghc.mk:28: recipe for target 'docs/users_guide/build-man/ghc.1' failed
make[1]: *** [docs/users_guide/build-man/ghc.1] Error 2
docs/users_guide/ghc.mk:16: recipe for target 'docs/users_guide/build-html/users_guide/index.html' failed
make[1]: *** [docs/users_guide/build-html/users_guide/index.html] Error 2
writing output... [100%] markup
/Users/carter/dev-checkouts/ghc-tree/ghc-8.4.4-checkout-clang-build/utils/haddock/doc/invoking.rst:457: WARNING: unknown option: -cpp
generating indices... genindex
writing additional pages... search
copying static files... done
copying extra files... done
dumping search index in English (code: en) ... done
dumping object inventory... done
build succeeded, 1 warning.

The HTML pages are in .build-html.
cp -R utils/haddock/doc/.build-html utils/haddock/doc/haddock
Makefile:122: recipe for target 'all' failed
make: *** [all] Error 2