ninja: move out of pythonPackages

ninja is a build system written in C++ that just happens to use python
to build/install *itself*. It is not a "python package".

After this commit, ninja will be at pkgs.ninja instead of
pkgs.pythonPackages.ninja.

pkgs/development/tools/build-managers/ninja/default.nix

@@ -0,0 +1,28 @@
+{ stdenv, fetchurl, unzip, python, asciidoc, re2c }:
+
+stdenv.mkDerivation rec {
+  name = "ninja-1.2.0";
+
+  src = fetchurl {
+    url = "https://github.com/martine/ninja/archive/v1.2.0.zip";
+    sha256 = "15ynh806ah37bqb57hcs3mj2g82900sncp6n3bssfggb4azgjlh3";
+  };
+
+  buildInputs = [ python asciidoc unzip re2c ];
+
+  buildPhase = ''
+    python bootstrap.py
+    asciidoc doc/manual.asciidoc
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp ninja $out/bin/
+
+    mkdir -p $out/share/doc/ninja
+    cp doc/manual.asciidoc $out/share/doc/ninja/
+    cp doc/manual.html $out/share/doc/ninja/
+  '';
+
+  homepage = http://martine.github.io/ninja/;
+}