GitLab

currently deepseq, parallel, stm.

We now use a tarball of it, so we don't want to get it from a darcs repo.

 - the package DB is a directory containing one file per package
   instance (#723)

 - there is a binary cache of the database (#593, #2089)

 - the binary package is now a boot package

 - there is a new package, bin-package-db, containing the Binary
   instance of InstalledPackageInfo for the binary cache.

Also included in this patch

 - Use colour in 'ghc-pkg list' to indicate broken or hidden packages
  
   Broken packages are red, hidden packages are 
  
   Colour support comes from the terminfo package, and is only used when
    - not --simple-output
    - stdout is a TTY
    - the terminal type has colour capability

 - Fix the bug that 'ghc-pkg list --user' shows everything as broken

Rather than indirecting through an integer package

integer-gmp's Integer is now wrapped by an Integer type in integer.

Ifdefs for whether we had extensible exceptions or not were spreading
through GHC's source, and things would only have got worse for the next
2-3 years, so instead we now use an implementation of extensible
exceptions built on top of the old exception type.

Everything will be changing in a couple of weeks anyway, so let's
just keep it simple for the time being.

* New packages format lets you select source control system in use
* Packages file now includes root repo explicitly
* Scripts darcs-all and push-all updated for the new packages format only
* New sync-all script, intended for use after Git changeover and for buildbots right now
* Had to remove libraries/bootstrapping from tree since Git cannot track empty directories without a hack
* Determine checkout date with Git using Darcs fallback in aclocal.m4

It has some sort of Error Monad using the old Exception type.
I'm not familiar with it enough to know what the right thing to do
for it with extensible exceptions is.

It's now easier to add new repos anywhere in the source tree