Fix up sandboxes to not use file database.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Revert "Replace a '>=' comparison with a '>'."

This reverts commit 440fe65e4f2e1f3859a0444c28c636ff905f82a4.
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>
Rename to instantiatedWith and store in InstalledPackageINfo

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Add uninterpreted required-signatures and exported-signatures fields.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Wire up so dep solver outputs different format, but trivial resolution

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

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Disconnect Dep from Real. We'll simplify soon. Note some dodginess in Distribution.Client.Freeze

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Remove unnecessary PackageId from InstallPlan InstalledPackage

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Remove unnecessary fixed depths, NOTE DODGINESS in change reporting

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Swap ConfiguredPackage to use InstalledPackageId deps, CONFIGURED PACKAGE PROBLEMS is now DODGY

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

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

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
WIP2

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
Indirect through fake map (and tracing to be removed)

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

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