Merge 'staging' into closure-size

- there were many easy merge conflicts
- cc-wrapper needed nontrivial changes

Many other problems might've been created by interaction of the branches,
but stdenv and a few other packages build fine now.

pkgs/development/tools/misc/texinfo/4.13a.nix

@@ -36,5 +36,6 @@ stdenv.mkDerivation rec {
     license = stdenv.lib.licenses.gpl3Plus;
 
     homepage = http://www.gnu.org/software/texinfo/;
+    branch = "4.13";
   };
 }

pkgs/development/tools/misc/texinfo/5.2.nix

@@ -39,5 +39,6 @@ stdenv.mkDerivation rec {
       need revise only that one document.  The Texinfo system is
       well-integrated with GNU Emacs.
     '';
+    branch = "5.2";
   };
 }