toxvpn: fix build with cmake4 (#453918)

pkgs/by-name/to/toxvpn/package.nix

@@ -37,6 +37,11 @@ stdenv.mkDerivation {
 
   cmakeFlags = lib.optionals stdenv.hostPlatform.isLinux [ "-DSYSTEMD=1" ];
 
+  postPatch = ''
+    substituteInPlace CMakeLists.txt \
+      --replace-fail "cmake_minimum_required(VERSION 2.6)" "cmake_minimum_required(VERSION 3.10)"
+  '';
+
   postInstall = "cp ${./bootstrap.json} $out/share/toxvpn/";
 
   installCheckPhase = "$out/bin/toxvpn -h";