Add sp compatibility wrapper

This wrapper is required by some old programs (e.g., po4a which I'm trying to package)

svn path=/nixpkgs/trunk/; revision=25320

pkgs/tools/text/sgml/opensp/compat.nix

@@ -0,0 +1,15 @@
+{ stdenv, opensp }:
+
+stdenv.mkDerivation {
+  name = "sp-compat-${builtins.substring 7 100 opensp.name}";
+
+  buildCommand = ''
+    mkdir -pv $out/bin
+    for i in ${opensp}/bin/o*; do
+      ln -sv $i $out/bin/''${i#${opensp}/bin/o}
+    done
+    '';
+
+  meta.description =
+    "Compatibility wrapper for old programs looking for original sp programs";
+}

pkgs/top-level/all-packages.nix

@@ -993,6 +993,8 @@ let
 
   opensp = callPackage ../tools/text/sgml/opensp { };
 
+  spCompat = callPackage ../tools/text/sgml/opensp/compat.nix { };
+
   openvpn = callPackage ../tools/networking/openvpn { };
 
   optipng = callPackage ../tools/graphics/optipng { };