Fixes for #508 and #510

Kind of resolves https://github.com/haskell/haddock/issues/508

This ended up causes far too many issues to be worthwhile. We'll just
have to live with inconsistent haddock documentation.

This reverts commit cec21957.

Fix #303. Hide footer when printing

Alabaster is now the default sphinx theme and is a significant
improvement over the previous default that it's worthproviding it when
unavailable (e.g. Sphinx <1.3).

The "Produced by Haddock" footer was overlapping the page's body when printing.
This patch hides the footer with a css media rule.

This is necessary to ensure we use gmake.

Apparently GHC's build system doesn't permit wildcards in clean paths.

This bump was a bit premature.

This reverts commit 7b238d9c.

Otherwise the html documentation won't be installed for binary-dist.

It appears the haddock insists on prefixing --hyperlinked-sourcer output
with directory which the source appeared in.

Currently, one can document top-level instance declarations, but derived
instances (both those in `deriving` clauses and standalone `deriving`
instances) do not enjoy the same privilege. This makes the necessary
changes to the Haddock API to enable rendering Haddock comments for
derived instances.

This is part of a fix for Trac #11768.

The variable reference was incorrectly escaped, meaning that Sphinx
documentation was never installed.

(cherry picked from commit 609018dd)

The variable reference was incorrectly escaped, meaning that Sphinx
documentation was never installed.

This relates to a big GHC patch for Trac #11348

(cherry picked from commit 5c82c9fc)