Fixes #2207.

GHC has been changed to guarantee producing valid object files for
signatures (they will usually be empty).

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

fix bootstrap sandbox help documentation

Preliminary support for compiling signature files, using --instantiate-with

There's no chrome here, but some of the guts for Cabal supporting compiling
signatures.  The key UI is a new --instantiate-with flag for ./Setup (no support
cabal-install side!) which properly modifies the package key, calculates extra
hole dependencies for a package, and ensures an appropriately
translated -sig-of is passed to GHC.  The UI here is supremely user-unfriendly:
the intent is that users will use cabal-install to calculate these parameters
for them.

ToDo: Cabal's inconsistency check in ./Setup needs to be adjusted to be
less zealous.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

add data-dir to InstalledPackageInfo

add ISC license

the datadir location for the inplace InstallDirs was pointing to the top directory
of the package instead of the directory containing the data. this has been fixed.
since templates have already been expanded at this point, datasubdir raises an
exception an cannot be used in generalInstalledPackageInfo. therefore the
full path is stored in datadir.

 SavedConfig Monoid instance: make list fields work like Flags.

Fixes #1884. See code comments for more details.

`deepseq-1.4.0.0`'s major change is in the default `rnf` method
implementation (see haskell/deepseq#1 for details). However, `Cabal` isn't affected
by that, and happily compiles against the current (yet unreleased) `deepseq-1.4.0.0`.

(approved by @dcoutts)

Prettify code to ensure compilation with -XNoMonomorphismRestriction

docs: change detailed-1.0 to detailed-0.9

It's not clear to me that there even is a detailed-1.0. I searched around the repository for something about it and I don't see anything.

Fixes #2211.

Bug fix: packagesThatDependOn should go through the fake map.

This fix got dropped shuffling PRs around when we committed
ff6c718b

'sandbox delete': exit with 0 even with 'require-sandbox: True'

Fixes #2203.

Consolidate exposed-modules and reexported-modules in InstalledPackageInfo

A note first: this patch does NOT modify the user-facing experience in Cabal
files; it only changes how we register information in the installed package
database.

This patch takes the exposed-modules and reexported-modules fields in
the InstalledPackageInfo structure and consolidates them into just the
exposed module fields, which now has a Maybe flag indicating if a
module is reexported and, if it is, what the original module was.  I've
also added in a field for signatures although it is currently unused.

The big benefit of this change is that it will make processing at the GHC level
much more uniform when we add signatures: signatures can also be reexported
and the new representation means we can share the code.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Fixes #2198.

Switch InstallPlan over to using IPID-indexed PackageIndex.

Remove build-depends from pkgDescrFieldDescrs

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Fixes #2195.

cabal-install: Fix PackageTests using user's config

- add struct PackageTests.PackageTester.TestsPaths
- contains absolute paths for cabal, ghc, cabal-config
- refactor to consequently use this as input for all tests