Distribution.Simple.Setup: remove job cap

Fixes #3191.

See https://github.com/well-typed/hackage-security/pull/151.

Warn when 'cabal configure' cannot resolve dependencies.

Revert "Add warning about testing Cabal on Windows"

This reverts commit 727f4479.

This comment is unnecessary after #3180. [ci skip]

Unbreak the build on AppVeyor.

Update HACKING.md: Add --allow-newer=Cabal

Fix exitcode on `upload`ing failure

This reverts commit 5a1f8575.

Cabal should be buildable out of the box.

hackage-security doesn't know about Cabal 1.25.

Skip Cabal package tests that cannot run in the current environment

The functions 'testWhen' and 'testUnless' filter tests in the 'TestTreeM' monad.
The option '--enable-all-tests' ignores filtering.  This commit also applies
filtering to the existing package tests that cannot run on Windows.

This reverts commit f211508d.

Don't pass OSX-specific options to GHC on non-OSX.

Basically a two-line change, the rest is about passing a 'Platform' value to
'renderGhcArgs'.

Allow limiting the scope of '--allow-newer'. 

[ci skip]

Before:

    allow-newer: False

After:

    -- allow-newer: False

Was accidentally broken in #3165.

Fixes #2756.

Warn user when deleting package database

Small tweaks to config file parsing.

Add field for setting framework search path (fixes #182).

* Renamed to 'extra-framework-dirs'.
* Added 'extra-framework-dirs' to ConfigFlags.
* Added some checks.
* Updated changelog.

Fixes #2381. If CABAL_SANDBOX_PACKAGE_PATH, GHC_PACKAGE_PATH, or
GHCJS_PACKAGE_PATH refer to a package database inside the sandbox, warn
the user that the package database has been deleted.