Fixes #1450.

See #1447.

Changes back the types of 'configCompiler' and 'configCompilerEx', but marks
them as deprecated. Adds new functions 'configCompilerEx' and
'configCompilerAuxEx'.

The remaining functions that changed type after the cross-compilation changes
shouldn't matter from the backwards compatibility standpoint:

    * InstallDirs.{absoluteInstallDirs, prefixRelativeInstallDirs,
      initialPathTemplateEnv} - the versions in D.S.LocalBuildInfo retain their
      old types and are usually used instead. In any case, removing the Platform
      parameter from here is problematic because the default install dirs now
      include $arch and $os vars.

    * D.S.Configure.configure - shouldn't be used by the setup scripts.

See #1214 for the original (backwards-incompatible) patches.

Helps to disambiguate Cabal's compat modules from cabal-install's.

Instead, just append '/path/to/.cabal-sandbox/packages' at the end.

See the discussion in #1402.

See #1362.

Distribution/Client/Sandbox.hs:695:9: parse error on input `}'

Also add 'configProgramArgs' and 'configProgramPaths' to the set of
special-cased flags.

Fixes #1360.

Allows to specify an alternate location for the sandbox config file
(@cabal.sandbox.config@) instead of the current directory.

Usage: 'cabal --sandbox-config-file=/path/to/config build'.

Fixes #1356.

Use the values from 'ConfigFlags' that were read from 'dist/setup-config'
instead.

This way 'reinstallAddSourceDeps' won't reinstall deps for the wrong compiler,
but the user will be forced to use 'install -w' when installing inside a
sandbox. This is consistent with the normal mode of operation.

Fixes #1333, in a way.

Fixes #1197.

This patch is a bit large because it includes several related changes:

1) Remove 'installUseSandbox' from 'InstallFlags' and pass 'useSandbox' as an
additional argument instead.

2) Instead of calling 'reinstallAddSourceDeps' from 'installAction', always pass
'SandboxPackageInfo' to 'install'.

3) Set the timestamps of newly-added add-source deps to 0 in the timestamp file.

4) Move the timestamp file update to 'postInstallActions' from
'withModifiedDeps'. This way, the timestamps are updated even when the user runs
'install --only-dependencies' or 'install some-add-source-dep-package-id'.

Fixes #1332.

Previously, we used a hack for reinstalling reverse dependencies: we created an
install plan for the sandboxed package and the modified add-source deps and then
pruned the sandboxed package from it. This missed those revdeps that the
sandboxed package didn't depend on and also broke the sandboxed package if it
was installed in the sandboxed package DB (see #1229).

This commit replaces that hack with a more principled approach: we create a plan
for the whole environment (all packages installed in the sandbox), constraining
the modified add-source deps to be reinstalled and the already installed
packages to be preferably not.

Fixes #1229.

Reverts 7b2e3630. Instead of temporarily setting
'configUserInstall' to 'False' in various places, we now just check that we're
not in a sandbox when deciding whether we should use 'rootCmd'.

Snapshot deps now behave more like `cabal-dev add-source`. Implemented by adding
a BuildTreeRefType field to the BuildRef index entry.

Fixes #1321.

This avoids the risk of conflicts if we use a single add-source dep with
multiple sandboxes.

Works better with 'cabal clean'.

Fixes #1281.

In rare cases, 'cabal.sandbox.config' and 'dist/setup-config' could
theoretically become desynchronised. Add a sanity check against this
possibility.

refold authored May 01, 2013 and Mikhail Glushenkov committed May 02, 2013

Separate listing package sources from copying them over. Allows us to remove a
bunch of code from 'D.C.Sandbox.Timestamp'.

So that we don't reinstall add-source deps for the wrong compiler (e.g. when
doing 'cabal build' after 'cabal install -w'). We already do this in configure,
and running 'install .' means configuring the current package.

Fixes #1265.

Also improve a message that gets printed when we find a cabal.config created by
cabal-dev.

We don't show that command in 'sandbox help' output by default, but if the user
is running 'list-sources', she probably wants to know about it.

Also make it possible to list ignored build tree refs (those present in the
index file but not in the source package DB).

Unlike 'cabal-dev', we don't create a tarball, but simply copy the files to a
private location.

Fixes #1143.