emacs30: add a patch to fix upstream bug 67916 (#361947)

pkgs/applications/editors/emacs/inhibit-lexical-cookie-warning-67916-30.patch

···
+From: Lin Jian <[e-mail]>
+Bug: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=67916
+
+Inhibit lexical cookie warning for *-pkg.el files (bug#67916)
+
+Users may use byte-compile-error-on-warn to turn compilation warnings
+into errors to make sure their Emacs lisp packages are warning-free.
+Emacs bug 67916 makes that difficult because the Emacs-generated file
+*-pkg.el emits a compilation warning about missing lexical cookie.
+
+There is an upstream patch to fix this.  That patch makes Emacs also
+generate the needed lexical cookie when generating *-pkg.el files.
+However, that patch has stalled.
+
+This patch takes an easier but less accurate approach by inhibiting
+lexical cookie warning for *-pkg.el files.  Given that not all
+*-pkg.el files are generated by Emacs, to reduce impact, this patch
+also checks no-byte-compile.
+
+--- a/lisp/emacs-lisp/bytecomp.el
++++ b/lisp/emacs-lisp/bytecomp.el
+@@ -2266,6 +2266,8 @@ See also `emacs-lisp-byte-compile-and-load'."
+               filename buffer-file-name))
+       ;; Don't inherit lexical-binding from caller (bug#12938).
+       (unless (or (local-variable-p 'lexical-binding)
++                  (and (string-suffix-p "-pkg.el" filename)
++                       (with-current-buffer input-buffer no-byte-compile))
+                   bytecomp--inhibit-lexical-cookie-warning)
+         (let ((byte-compile-current-buffer (current-buffer)))
+           (displaying-byte-compile-warnings

pkgs/applications/editors/emacs/sources.nix

···
     variant = "mainline";
     rev = "30.0.92";
     hash = "sha256-V2TXLemSCIPTpg6RDChv4va7pHfVcqSMw/EWqvlRQ1o=";
+    patches = fetchpatch: [
+      ./inhibit-lexical-cookie-warning-67916-30.patch
+    ];
   });
 
   emacs28-macport = import ./make-emacs.nix (mkArgs {