Formatting.
Add 'suppressOverrideArgs'.
Ignore 'ghc-options' when parsing 'ghc --info' output.

Fixes #1438.
Rearrange the code a bit.
Merge pull request #1440 from 23Skidoo/ghc-info-ignore-ghc-options

Ignore 'ghc-options' when parsing 'ghc --info' output.
Unit tests: use configure GHC

This means that the package tests will pick up whatever GHC was passed
on the

    cabal configure --enable-tests -w some-ghc

command line.
Fix the 'index.cache' up-to-date check.

Comparison was using (>) instead of (>=). Bug introduced in 272a5c2c.
Fixes #1443.
Give the xxx_HOST_OS and xxx_HOST_ARCH options that were probed from ghc's target
platform, rather than assuming HOST == BUILD. This fixes things for cross compiling.