$docdev fixups: mostly to avoid empty output

... after auto-removing some kinds of files by default.
In some cases I let them be removed and in others I let them be put into
$docdev. That was more due to general indecisiveness on this question
than any reasons in the particular cases.

pkgs/development/libraries/libidn/default.nix

@@ -8,12 +8,10 @@ stdenv.mkDerivation rec {
     sha256 = "1xf4hphhahcjm2xwx147lfpsavjwv9l4c2gf6hx71zxywbz5lpds";
   };
 
-  outputs = [ "dev" "out" "bin" "info" "doc" ]; # $doc has just man3
+  outputs = [ "dev" "out" "bin" "info" "docdev" ];
 
   doCheck = ! stdenv.isDarwin;
 
-  postFixup = ''_moveToOutput share/man/man1 "$bin" '';
-
   meta = {
     homepage = http://www.gnu.org/software/libidn/;
     description = "Library for internationalized domain names";