ABI check tweaks and fix

ghc.spec

@@ -434,14 +434,19 @@ make test
 
 # check the ABI hashes
 %if %{undefined ghc_bootstrapping}
+echo "Checking package ABI hashes..."
 for i in %{ghc_packages_list}; do
   old=$(ghc-pkg field $i id --simple-output)
   new=$(/usr/libexec/ghc-pkg/wrapper %{buildroot}%{ghclibdir} field $i id --simple-output)
   if [ "$old" != "$new" ]; then
-   echo "ABI hash for $i changed!:"
+    echo "ABI hash for $i changed!:" >&2
-   echo "$old -> $new"
+    echo "  $old -> $new" >&2
     exit 1
+  else
+    echo "($old unchanged)"
+  fi
 done
+echo "done."
 %endif