build primus for both 32 and 64 and a primusrun that references both

pkgs/tools/X11/primus/builder.sh

@@ -3,10 +3,10 @@ source $stdenv/setup
 cp -r $src src
 cd src
 
-export LIBDIR=$out/x86_64
+export LIBDIR=$out/lib
 export PRIMUS_libGLa=$nvidia/lib/libGL.so
-export PRIMUS_libGLd=/var/run/opengl-driver/lib/libGL.so
-export PRIMUS_LOAD_GLOBAL=/var/run/opengl-driver/lib/libglapi.so
+export PRIMUS_libGLd=$mesa/lib/libGL.so
+export PRIMUS_LOAD_GLOBAL=$mesa/lib/libglapi.so
 
 make
-ln -s $out/x86_64/libGL.so.1 $out/x86_64/libGL.so
+ln -s $out/libGL.so.1 $out/libGL.so

pkgs/tools/X11/primus/default.nix

@@ -1,20 +1,22 @@
-{ stdenv, fetchgit
-, x11, mesa
-, linuxPackages
+{ stdenv
+, primusLib_x64
+, primusLib_i686
+, writeScript
 }:
 let
   version = "1.0.0";
+  primusrun = writeScript "primusrun"
+''
+  export LD_LIBRARY_PATH=${primusLib_x64}/lib:${primusLib_i686}/lib
+  exec "$@"
+'';
 in
 stdenv.mkDerivation {
   name = "primus-${version}";
-  src = fetchgit {
-    url = git://github.com/amonakov/primus.git;
-    rev = "074817614c014e3a99259388cb18fd54648b659a";
-    sha256 = "0mrh432md6zrm16avxyk57mgszrqpgwdjahspchvlaccqxp3x82v";
-  };
-
-  nvidia = linuxPackages.nvidia_x11;
-
-  buildInputs = [ x11 mesa ];
-  builder = ./builder.sh;
+  builder = writeScript "builder"
+  ''
+  source $stdenv/setup
+  mkdir -p $out/bin
+  cp ${primusrun} $out/bin/primusrun
+  '';
 }

pkgs/tools/X11/primus/lib.nix

@@ -0,0 +1,20 @@
+{ stdenv, fetchgit
+, x11, mesa
+, nvidia
+}:
+let
+  version = "1.0.0";
+in
+stdenv.mkDerivation {
+  name = "primus-lib-${version}";
+  src = fetchgit {
+    url = git://github.com/amonakov/primus.git;
+    rev = "074817614c014e3a99259388cb18fd54648b659a";
+    sha256 = "0mrh432md6zrm16avxyk57mgszrqpgwdjahspchvlaccqxp3x82v";
+  };
+
+  inherit nvidia mesa;
+
+  buildInputs = [ x11 mesa ];
+  builder = ./builder.sh;
+}

pkgs/top-level/all-packages.nix

@@ -9327,6 +9327,13 @@ let
   virtualgl = callPackage ../tools/X11/virtualgl { };
 
   primus = callPackage ../tools/X11/primus {
+    inherit writeScript;
+    primusLib_x64 = callPackage ../tools/X11/primus/lib.nix {
+      nvidia = linuxPackages.nvidia_x11;
+    };
+    primusLib_i686 = callPackage_i686 ../tools/X11/primus/lib.nix {
+      nvidia = callPackage_i686 ../os-specific/linux/nvidia-x11 { libsOnly = true; };
+    };
   };
 
   bumblebee = callPackage ../tools/X11/bumblebee {