Added fetchcvs.

svn path=/nixpkgs/trunk/; revision=5295

pkgs/build-support/fetchcvs/builder.sh

@@ -0,0 +1,24 @@
+source $stdenv/setup
+
+header "exporting $url $module into $out"
+
+prefetch=$(dirname $out)/cvs-checkout-tmp-$outputHash
+echo $prefetch
+if test -e "$prefetch"; then
+    mv $prefetch $out
+else
+    if test -z "$tag"; then
+      rtag="-DNOW"
+    else
+      rtag="-r $tag"
+    fi
+    cvs -f -d $url export $rtag -d $out $module
+fi
+
+actual=$(nix-hash $out)
+if test "$actual" != "$outputHash"; then
+    echo "hash is $actual, expected $outputHash" >&2
+    exit 1
+fi
+
+stopNest