bicon: unstable-2018-09-10 -> unstable-2020-06-04

Without the update build fails on -fno-common toolchains as:

    $ nix build --impure --expr 'with import ./. {}; bicon.override { stdenv = clang13Stdenv; }'
    ...
    ld: bicon_bin-bicon_read.o:/build/source/bicon/bicon_read.c:37:
      multiple definition of `bicon_options'; bicon_bin-bicon.o:/build/source/bicon/./bicon_read.h:4: first defined here

While at it pulled in pending fix for clang compatibility.

pkgs/applications/misc/bicon/default.nix

@@ -1,24 +1,35 @@
 { lib, stdenv
-  , fetchFromGitHub
-  , autoreconfHook
-  , pkg-config
-  , perl
-  , fribidi
-  , kbd
-  , xkbutils
+, fetchFromGitHub
+, fetchpatch
+, autoreconfHook
+, pkg-config
+, perl
+, fribidi
+, kbd
+, xkbutils
 }:
 
 stdenv.mkDerivation rec {
   pname = "bicon";
-  version = "unstable-2018-09-10";
+  version = "unstable-2020-06-04";
 
   src = fetchFromGitHub {
     owner = "behdad";
     repo = pname;
-    rev = "38725c062a83ab19c4e4b4bc20eb9535561aa76c";
-    sha256 = "0hdslrci8pq300f3rrjsvl5psfrxdwyxf9g2m5g789sr049dksnq";
+    rev = "64ae10c94b94a573735a2c2b1502334b86d3b1f7";
+    sha256 = "0ixsf65j4dbdl2aazjc2j0hiagbp6svvfwfmyivha0i1k5yx12v1";
   };
 
+  patches = [
+    # Fix build on clang-13. Pull the change pending upstream
+    # inclusion: https://github.com/behdad/bicon/pull/29
+    (fetchpatch {
+      name = "clang.patch";
+      url = "https://github.com/behdad/bicon/commit/20f5a79571f222f96e07d7c0c5e76e2c9ff1c59a.patch";
+      sha256 = "0l1dm7w52k57nv3lvz5pkbwp021mlsk3csyalxi90np1lx5sqbd1";
+    })
+  ];
+
   buildInputs = [ fribidi kbd xkbutils perl ];
   nativeBuildInputs = [ autoreconfHook pkg-config ];