Merge branch 'master' into staging

Resolved the following conflicts (by carefully applying patches from the both
branches since the fork point):

   pkgs/development/libraries/epoxy/default.nix
   pkgs/development/libraries/gtk+/3.x.nix
   pkgs/development/python-modules/asgiref/default.nix
   pkgs/development/python-modules/daphne/default.nix
   pkgs/os-specific/linux/systemd/default.nix

pkgs/tools/text/html-tidy/default.nix

@@ -4,13 +4,13 @@
 
 stdenv.mkDerivation rec {
   name = "html-tidy-${version}";
-  version = "5.4.0";
+  version = "5.6.0";
 
   src = fetchFromGitHub {
     owner = "htacg";
     repo = "tidy-html5";
     rev = version;
-    sha256 = "1q9ag2dh2j636fw9vyz6gg0kiss8p6lvj22h25nqsw0daan57c32";
+    sha256 = "0w175c5d1babq0w1zzdzw9gl6iqbgyq58v8587s7srp05y3hwy9k";
   };
 
   nativeBuildInputs = [ cmake libxslt/*manpage*/ ];

pkgs/tools/text/mpage/default.nix

@@ -3,7 +3,7 @@
 stdenv.mkDerivation rec {
   name = "mpage-2.5.6";
   src = fetchurl {
-    url = "http://www.mesa.nl/pub/mpage/${name}.tgz";
+    url = "http://www.libGLU_combined.nl/pub/mpage/${name}.tgz";
     sha256 = "016w9sm06sn1d2lim4p8fzl6wbmad3wigxhflsybzi7p4zy6vrjg";
   };
 
@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
     '';
 
     license = "liberal";  # a non-copyleft license, see `Copyright' file
-    homepage = http://www.mesa.nl/pub/mpage/;
+    homepage = http://www.libGLU_combined.nl/pub/mpage/;
     platforms = stdenv.lib.platforms.linux;
   };
 }