zsh: fix configure script with clang 16

While zsh builds, the resulting zsh is broken on Darwin.

pkgs/shells/zsh/default.nix

@@ -30,6 +30,13 @@ stdenv.mkDerivation {
   patches = [
     # fix location of timezone data for TZ= completion
     ./tz_completion.patch
+    # Fixes configure misdetection when using clang 16, resulting in broken subshells on Darwin.
+    # This patch can be dropped with the next release of zsh.
+    (fetchpatch {
+      url = "https://github.com/zsh-users/zsh/commit/ab4d62eb975a4c4c51dd35822665050e2ddc6918.patch";
+      hash = "sha256-nXB4w7qqjZJC7/+CDxnNy6wu9qNwmS3ezjj/xK7JfeU=";
+      excludes = [ "ChangeLog" ];
+    })
   ];
 
   strictDeps = true;