light: pull upstream fix for -fno-common toolchains

Without the change ubuild fails on gcc-10 as:

    ld: impl/light-razer.o:/build/source/src/helpers.h:24: multiple definition of
      `light_loglevel'; light-main.o:/build/source/src/helpers.h:24: first defined here

pkgs/os-specific/linux/light/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitHub, autoreconfHook, coreutils }:
+{ lib, stdenv, fetchFromGitHub, fetchpatch, autoreconfHook, coreutils }:
 
 stdenv.mkDerivation rec {
   version = "1.2.2";
@@ -10,6 +10,16 @@ stdenv.mkDerivation rec {
     sha256 = "1a70zcf88ifsnwll486aicjnh48zisdf8f7vi34ihw61kdadsq9s";
   };
 
+  patches = [
+    # Pull upstream fix for -fno-common toolchains:
+    #  https://github.com/haikarainen/light/pull/135
+    (fetchpatch {
+      name = "fno-common.patch";
+      url = "https://github.com/haikarainen/light/commit/eae912ca7ff3356805e47739114861d2b6ae7ec0.patch";
+      sha256 = "15jp8hm5scl0myiy1jmvd6m52lhx5jscvi3rgb5siwakmnkgzx9j";
+    })
+  ];
+
   configureFlags = [ "--with-udev" ];
 
   nativeBuildInputs = [ autoreconfHook ];