Fix installation of package dependencies for GHC HEAD
Neither build system works with GHC HEAD at the moment.
The Make build system is currently not equipped to install the needed SRC_DEPS
at all.
Shake tries to do so, but fails for GHC HEAD, because it needs head.hackage overlays.
There are two items here:
- Fix the Shake build system to call
$(path to head hackage repo)/scripts/head.hackage.sh init-local
(possibly just copy over that shell script) and thencabal install --lib $SRC_DEPS --package-env=nofib.env
. Then addHC_FLAGS=--package-env=$(TOP)/nofib.env
. - Fix the Make build system to do the same.
Depending on how good (1) works, we might not need (2).