firefoxPackages: fix builds by a patch from Arch

pkgs/applications/networking/browsers/firefox/packages.nix

@@ -4,6 +4,13 @@ let
 
   common = opts: callPackage (import ./common.nix opts) {};
 
+  # Needed on older branches since rustc: 1.32.0 -> 1.33.0
+  missing-documentation-patch = fetchurl {
+    name = "missing-documentation.patch";
+    url = "https://aur.archlinux.org/cgit/aur.git/plain/deny_missing_docs.patch"
+        + "?h=firefox-esr&id=03bdd01f9cf";
+    sha256 = "1i33n3fgwc8d0v7j4qn7lbdax0an6swar12gay3q2nwrhg3ic4fb";
+  };
 in
 
 rec {
@@ -74,6 +81,8 @@ rec {
       # this one is actually an omnipresent bug
       # https://bugzilla.mozilla.org/show_bug.cgi?id=1444519
       ./fix-pa-context-connect-retval.patch
+
+      missing-documentation-patch
     ];
 
     meta = firefox.meta // {
@@ -139,6 +148,7 @@ in rec {
 
     patches = [
       ./no-buildconfig.patch
+      missing-documentation-patch
     ];
   };
 
@@ -243,6 +253,10 @@ in rec {
       rev   = "dda14213c550afc522ef0bb0bb1643289c298736";
       sha256 = "0lj79nczcix9mx6d0isbizg0f8apf6vgkp7r0q7id92691frj7fz";
     };
+
+    patches = [
+      missing-documentation-patch
+    ];
   };
 
   tor-browser = tor-browser-8-0;