Add package 'cpulimit'.

pkgs/tools/misc/cpulimit/default.nix

@@ -0,0 +1,26 @@
+{stdenv, fetchurl}:
+
+stdenv.mkDerivation rec {
+  name = "cpulimit-${version}";
+  version = "2.2";
+
+  src = fetchurl {
+    url = "mirror://sourceforge/limitcpu/${name}.tar.gz";
+    sha256 = "1r19rk2cbyfmgwh3l445fxkn1bmkzyi69dg5dbx4b4mbqjjxlr1z";
+  };
+
+  buildFlags = with stdenv;
+    if isDarwin then "osx"
+    else if isFreeBSD then "freebsd"
+    else "cpulimit";
+
+  installFlags = "PREFIX=$(out)";
+
+  meta = with stdenv.lib; {
+    homepage = "http://limitcpu.sourceforge.net/";
+    description = "A tool to throttle the CPU usage of programs";
+    platforms = with platforms; [linux freebsd darwin];
+    license = licenses.gpl2;
+    maintainer = [maintainers.rycee];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -733,6 +733,8 @@ let
     flex = flex_2_5_35;
   };
 
+  cpulimit = callPackage ../tools/misc/cpulimit { };
+
   crawlTiles = callPackage ../games/crawl { };
 
   crawl = callPackage ../games/crawl {