New license-files field.

Based closely on the patches by Mathieu Boespflug <mboes@cs.mcgill.ca>

This field is intended to be used instead of (or in addition to) the
normal 'license-file' field by packages that have multiple files for
their license material. This is useful when eg the license is
supplemented by additional permissions and/or conditions. Notably,
the LGPL is structured in this way: it amends the GPL with additional
permissions, therefore one should distribute both the GPL in COPYING
and the LGPL in COPYING.LESSER.

So we keep both the license-file and license-files fields (rather than
deprecating one) and packages can use either or a mixture.
Merge pull request #1642 from dcoutts/mboes-master

New license-files field.
Remove ambiguous import of 'catch'

Running 'cabal install Cabal/ cabal-install/' from the latest git version resulted in:

Distribution/Client/Compat/Process.hs:41:5:
    Ambiguous occurrence `catch'
    It could refer to either `Prelude.catch',
                             imported from `Prelude' at Distribution/Client/Compat/Process.hs:16:8-41
                             (and originally defined in `System.IO.Error')
                          or `Control.Exception.catch',
                             imported from `Control.Exception' at Distribution/Client/Compat/Process.hs:20:37-41
                             (and originally defined in `Control.Exception.Base')


This pull requests fixes that.
Merge pull request #1644 from djv/patch-4

Remove ambiguous import of 'catch'
Unbreak the build on GHC 7.6.3.

See #1644.
Remove a redundant equation.

'display IOS' already evaluates to "ios".
Add some more OS aliases.

Fixes #1641. Based on a patch by Karel Gardas.

The 'Compat' classification strictness type is confusing and should IMO be
merged with 'Permissive'.
Update bootstrap.sh: text 1.1.0.0, parsec 3.1.5
Merge pull request #1645 from tuncer/bootstrap-parsec-text

Update bootstrap.sh: text 1.1.0.0, parsec 3.1.5
add Eq instance for CDialect
Merge pull request #1650 from JohnLato/master

add Eq instance for CDialect
Remove cabal.config

ghc-options doesn't work on my version of cabal (1.18) and it gives
annoying warnings.
update Hackage download URL in bootstrap.sh

Downloading was failing with curl which seems
not do http redirect by default.

This change simple updates the urls from

Hackage 1's http://hackage.haskell.org/packages/archive/$PKG/$VER/$PKG-$VER.tar.gz to
Hackage 2's http://hackage.haskell.org/package/$PKG-$VER/$PKG-$VER.tar.gz

which makes curl happy and downloads work again.
Merge pull request #1655 from juhp/patch-1

update Hackage download URL in bootstrap.sh
Don't wipe .a metadata on ARM.

See https://github.com/haskell/cabal/pull/1537#issuecomment-33346143 .
Don't use -dylib-install-name on OS X with GHC > 7.8.

Fixes #1660. Based on a patch by Christiaan Baaij.
Merge pull request #1661 from 23Skidoo/no-dylib-install-name

Don't use -dylib-install-name on OS X with GHC > 7.8.
Add BSD2, close #1649
Add MPL-2.0, close #1654
Allow CC and LD be specified as environment variables when bootstrapping.