gmime: init at 3.0.1, leave 2.6.23 as is

This needs to be added as a separate package because API changed in 3.0, see:

https://mail.gnome.org/archives/gmime-devel-list/2017-April/msg00002.html
https://developer.gnome.org/gmime/3.0/gmime-changes-3-0.html
https://github.com/jstedfast/gmime/blob/3fd646c95503acb0d11bf67afde1c7bdd4fcc341/PORTING

pkgs/development/libraries/gmime/3.nix

···
+{ stdenv, fetchurl, pkgconfig, glib, zlib, gpgme, libidn, gobjectIntrospection }:
+
+stdenv.mkDerivation rec {
+  name = "gmime-3.0.1";
+
+  src = fetchurl {
+    url = "mirror://gnome/sources/gmime/3.0/${name}.tar.xz";
+    sha256 = "001y93b8mq9alzkvli6vfh3pzdcn5c5iy206ml23lzhhhvm5k162";
+  };
+
+  outputs = [ "out" "dev" ];
+
+  nativeBuildInputs = [ pkgconfig gobjectIntrospection ];
+  propagatedBuildInputs = [ glib zlib gpgme libidn ];
+  configureFlags = [ "--enable-introspection=yes" ];
+
+  enableParallelBuilding = true;
+
+  meta = with stdenv.lib; {
+    homepage = https://github.com/jstedfast/gmime/;
+    description = "A C/C++ library for creating, editing and parsing MIME messages and structures";
+    license = licenses.lgpl21Plus;
+    maintainers = with maintainers; [ chaoflow ];
+    platforms = platforms.unix;
+  };
+}

pkgs/development/libraries/gmime/default.nix pkgs/development/libraries/gmime/2.nix

···
 
   enableParallelBuilding = true;
 
-  meta = {
+  meta = with stdenv.lib; {
     homepage = https://github.com/jstedfast/gmime/;
     description = "A C/C++ library for creating, editing and parsing MIME messages and structures";
-    maintainers = [ stdenv.lib.maintainers.chaoflow ];
-    platforms = stdenv.lib.platforms.unix;
+    license = licenses.lgpl21Plus;
+    maintainers = with maintainers; [ chaoflow ];
+    platforms = platforms.unix;
   };
 }

pkgs/top-level/all-packages.nix

···
 
   glui = callPackage ../development/libraries/glui {};
 
-  gmime = callPackage ../development/libraries/gmime { };
+  gmime2 = callPackage ../development/libraries/gmime/2.nix { };
+  gmime3 = callPackage ../development/libraries/gmime/3.nix { };
+  gmime = gmime2;
 
   gmm = callPackage ../development/libraries/gmm { };