linux_5_11: init at 5.11

pkgs/os-specific/linux/kernel/linux-5.11.nix

@@ -0,0 +1,18 @@
+{ lib, buildPackages, fetchurl, perl, buildLinux, modDirVersionArg ? null, ... } @ args:
+
+with lib;
+
+buildLinux (args // rec {
+  version = "5.11";
+
+  # modDirVersion needs to be x.y.z, will automatically add .0 if needed
+  modDirVersion = if (modDirVersionArg == null) then concatStringsSep "." (take 3 (splitVersion "${version}.0")) else modDirVersionArg;
+
+  # branchVersion needs to be x.y
+  extraMeta.branch = versions.majorMinor version;
+
+  src = fetchurl {
+    url = "mirror://kernel/linux/kernel/v5.x/linux-${version}.tar.xz";
+    sha256 = "1d37w0zvmf8c1l99xvy1hy6p55icjhmbsv7f0amxy2nly1a7pw04";
+  };
+} // (args.argsOverride or {}))