validate requires haddock to be installed

[thorkilnaur]

A validate of a recent GHC HEAD on a machine that didn't have haddock installed ended with the report:

if ifBuildable/ifBuildable ghc-prim; then \
  cd ghc-prim && setup/Setup haddock --html-location='../$pkg' \
                               ; \
fi
Setup: haddock version >=0.6 is required but it could not be found.
make[1]: *** [doc.library.ghc-prim] Error 1
make[1]: Leaving directory `/usr/home/tn/tn/GHCDarcsRepository/ghc-HEAD-complete-20080503_0226/ghc/libraries'
make: *** [stage1] Error 2

This requirement is not mentioned on  http://hackage.haskell.org/trac/ghc/wiki/Building/Prerequisites and ought, if kept, to be checked and reported in the initial configure phase.

Best regards Thorkil

[igloo]

This is a bit fiddly - it's Cabal that finds haddock, so it's hard to know if it will succeed or not. Maybe we should detect it ourselves instead, and tell Cabal where to find it.

[igloo]

We now do tell Cabal where to find haddock, and this means we can fail early if we can't find it. This ticket is therefore fixed by:

Sun Jul 13 17:53:05 BST 2008  Ian Lynagh <igloo@earth.li>
  * If HADDOCK_DOCS is YES, then fail the build early if we couldn't find haddock
  This fixes trac #2266.