diff --git a/pkgs/tools/X11/xwinmosaic/default.nix b/pkgs/tools/X11/xwinmosaic/default.nix
index af17f3ade7d..51ba815f1de 100644
--- a/pkgs/tools/X11/xwinmosaic/default.nix
+++ b/pkgs/tools/X11/xwinmosaic/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitHub, gtk2, cmake, pkg-config, libXdamage }:
+{ lib, stdenv, fetchFromGitHub, fetchpatch, gtk2, cmake, pkg-config, libXdamage }:
 
 stdenv.mkDerivation rec {
   version = "0.4.2";
@@ -11,6 +11,16 @@ stdenv.mkDerivation rec {
     sha256 = "16qhrpgn84fz0q3nfvaz5sisc82zk6y7c0sbvbr69zfx5fwbs1rr";
   };
 
+  patches = [
+    # Pull upstream fix for -fno-common toolchains like upstream gcc-10:
+    #  https://github.com/soulthreads/xwinmosaic/pull/33
+    (fetchpatch {
+      name = "fno-common.patch";
+      url = "https://github.com/soulthreads/xwinmosaic/commit/a193a3f30850327066e5a93b29316cba2735e10d.patch";
+      sha256 = "0qpk802j5x6bsfvj6jqw1nz482jynwyk7yrrh4bsziwc53khm95q";
+    })
+  ];
+
   nativeBuildInputs = [ pkg-config cmake ];
   buildInputs = [ gtk2 libXdamage ];