Add scripts for testing compatability with hackage packages

So far just a test that all the non-trivial Setup.(l)hs scripts
compile. This only tests the latest versions, though if one were
to download a complete archive then one could test them all.
To speed up the check we skip Setup.hs scripts that have fewer
than 22 words. Below this cutoff there are no custom hooks and
it catches the great majority of scripts which greatly speeds up
the check.

tests/hackage/check.sh

+#!/bin/sh
+
+base_version=1.2.3.0
+test_version=1.3.9
+
+for setup in archive/*/*/Setup.hs archive/*/*/Setup.lhs; do
+
+  pkgname=$(basename ${setup})
+  
+  if test $(wc -w < ${setup}) -gt 21; then
+    if ghc -package Cabal-${base_version} -S ${setup} -o /dev/null 2> /dev/null; then
+
+      if ghc -package Cabal-${test_version} -S ${setup} -o /dev/null 2> /dev/null; then
+        echo "OK ${setup}"
+      else
+        echo "FAIL ${setup} does not compile with Cabal-${test_version}"     
+      fi
+    else
+      echo "OK ${setup} (does not compile with Cabal-${base_version})" 
+    fi
+  else
+    echo "trivial ${setup}"
+  fi
+
+done

tests/hackage/download.sh

+#!/bin/sh
+
+if test ! -f archive/archive.tar; then
+
+  wget http://hackage.haskell.org/cgi-bin/hackage-scripts/archive.tar
+  mkdir -p archive
+  mv archive.tar archive/
+  tar -C archive -xf archive/archive.tar    
+
+fi
+
+if test ! -f archive/00-index.tar.gz; then
+
+  wget http://hackage.haskell.org/packages/archive/00-index.tar.gz
+  mkdir -p archive
+  mv 00-index.tar.gz archive/
+  tar -C archive -xzf archive/00-index.tar.gz
+
+fi

tests/hackage/unpack.sh

+#!/bin/sh
+
+for tarball in archive/*/*/*.tar.gz; do
+
+  pkgdir=$(dirname ${tarball})
+  pkgname=$(basename ${tarball} .tar.gz)
+
+  if tar -tzf ${tarball} ${pkgname}/Setup.hs 2> /dev/null; then
+    tar -xzf ${tarball} ${pkgname}/Setup.hs -O > ${pkgdir}/Setup.hs
+  elif tar -tzf ${tarball} ${pkgname}/Setup.lhs 2> /dev/null; then
+    tar -xzf ${tarball} ${pkgname}/Setup.lhs -O > ${pkgdir}/Setup.lhs
+  else
+    echo "${pkgname} has no Setup.hs or .lhs at all!!?!"
+  fi
+
+done