Revert "Merge #255483: krb5: 1.20.1 -> 1.21.2"

This reverts commit d829719226, reversing
changes made to 93c0a7c196.

Some packages started missing kerberos framework on darwin.
https://github.com/NixOS/nixpkgs/pull/255483#issuecomment-1747218729
https://hydra.nixos.org/build/237078859/nixlog/5/tail

So for now we'll do a patch-level bump instead to fix security issues.

pkgs/development/libraries/kerberos/krb5.nix

@@ -1,5 +1,5 @@
 { lib, stdenv, fetchurl, pkg-config, perl, bison, bootstrap_cmds
-, openssl, openldap, libedit, keyutils, libverto, darwin
+, openssl, openldap, libedit, keyutils, libverto
 
 # for passthru.tests
 , bind
@@ -27,11 +27,11 @@ let
 in
 stdenv.mkDerivation rec {
   pname = "${type}krb5";
-  version = "1.21.2";
+  version = "1.20.1";
 
   src = fetchurl {
     url = "https://kerberos.org/dist/krb5/${lib.versions.majorMinor version}/krb5-${version}.tar.gz";
-    sha256 = "sha256-lWCUGp2EPAJDpxsXp6xv4xx867W845g9t55Srn6FBJE=";
+    sha256 = "sha256-cErtSbGetacXizSyhzYg7CmdsIdS1qhXT5XUGHmriFE=";
   };
 
   outputs = [ "out" "dev" ];
@@ -56,11 +56,7 @@ stdenv.mkDerivation rec {
   buildInputs = [ openssl ]
     ++ lib.optionals (stdenv.hostPlatform.isLinux && stdenv.hostPlatform.libc != "bionic" && !(stdenv.hostPlatform.useLLVM or false)) [ keyutils ]
     ++ lib.optionals (!libOnly) [ openldap libedit ]
-    ++ lib.optionals withVerto [ libverto ]
-    ++ lib.optionals stdenv.isDarwin (with darwin.apple_sdk; [
-      libs.xpc
-      frameworks.Kerberos
-    ]);
+    ++ lib.optionals withVerto [ libverto ];
 
   sourceRoot = "krb5-${version}/src";