Added Idris and updated fetchdarcs.

svn path=/nixpkgs/trunk/; revision=15595

pkgs/build-support/fetchdarcs/builder.sh

@@ -5,11 +5,14 @@ tagflags=""
 if test -n "$tag"; then
     tagtext="(tag $tag) "
     tagflags="--tag=$tag"
+elif test -n "$context"; then
+    tagtext="(context) "
+    tagflags="--context=$context"
 fi
 
 header "getting $url $partial ${tagtext} into $out"
 
-darcs get --no-pristine-tree $partial $tagflags "$url" "$out"
+darcs get --lazy --ephemeral $tagflags "$url" "$out"
 # remove metadata, because it can change
 rm -rf "$out/_darcs"