Merge branch 'master' into staging-next

There were several more conflicts from name -> pname+version;
all auto-solved by kdiff3, hopefully OK.

Hydra nixpkgs: ?compare=1538611

pkgs/applications/networking/irc/weechat/scripts/default.nix

@@ -6,7 +6,7 @@
   };
 
   weechat-matrix-bridge = callPackage ./weechat-matrix-bridge {
-    inherit (luaPackages) cjson;
+    inherit (luaPackages) cjson luaffi;
   };
 
   wee-slack = callPackage ./wee-slack {

pkgs/applications/networking/irc/weechat/scripts/weechat-matrix-bridge/default.nix

@@ -31,9 +31,9 @@ stdenv.mkDerivation {
     mkdir -p $out/{share,lib}
 
     cp {matrix.lua,olm.lua} $out/share
-    cp ${cjson}/lib/lua/5.2/cjson.so $out/lib/cjson.so
+    cp ${cjson}/lib/lua/${cjson.lua.luaversion}/cjson.so $out/lib/cjson.so
     cp ${olm}/lib/libolm.so $out/lib/libolm.so
-    cp ${luaffi}/lib/ffi.so $out/lib/ffi.so
+    cp ${luaffi}/lib/lua/${luaffi.lua.luaversion}/ffi.so $out/lib/ffi.so
   '';
 
   meta = with stdenv.lib; {