Change 'grub-mkrescue' to honor the 'GRUB_FAT_SERIAL_NUMBER'
environment variable.  That way, the caller can specify a fixed
serial number (instead of the randomly chosen one) to create EFI
images (the 'efi.img' file) that are reproducible bit-for-bit.

Patch by Ludovic Courtès <ludo@gnu.org>.
Mangled (for GRUB 2.04) by Tobias Geerinckx-Rice <me@tobias.gr>.

--- grub-2.04/util/grub-mkrescue.c	2019-05-20 13:01:11.000000000 +0200
+++ grub-2.04/util/grub-mkrescue.c	2019-07-08 23:57:36.912104652 +0200
@@ -809,8 +809,15 @@
       free (efidir_efi_boot);
 
       efiimgfat = grub_util_path_concat (2, iso9660_dir, "efi.img");
-      rv = grub_util_exec ((const char * []) { "mformat", "-C", "-f", "2880", "-L", "16", "-i",
-	    efiimgfat, "::", NULL });
+
+      const char *fat_serial_number = getenv ("GRUB_FAT_SERIAL_NUMBER");
+      const char *mformat_args[] =
+       { "mformat", "-C", "-f", "2880", "-L", "16",
+         fat_serial_number != NULL ? "-N" : "-C",
+         fat_serial_number != NULL ? fat_serial_number : "-C",
+         "-i", efiimgfat, "::", NULL };
+
+      rv = grub_util_exec (mformat_args);
       if (rv != 0)
 	grub_util_error ("`%s` invocation failed\n", "mformat");
       rv = grub_util_exec ((const char * []) { "mcopy", "-s", "-i", efiimgfat, efidir_efi, "::/", NULL });
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<tr><td><span title='2023-07-11 22:28:52 -0500'>2023-07-11</span></td><td><a href='/guix/commit/gnu/packages/patches/nix-dont-build-html-doc.diff?id=b5baa98053363180a2dedcb11c96efcf5bd20ece'>gnu: nix: Update to 2.16.1.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/package-management.scm (nix): Update to 2.16.1.
[source]: Use HTTPS for package source.
[inputs]: Add nlohmann-json.
[native-inputs]: Add rapidcheck.
[arguments]&lt;#:phases&gt;: In phase "check", change the value of environment
variable  "NIX_STORE" to "/nix/store" temporarily.

* gnu/packages/patches/nix-dont-build-html-doc.diff: Update.

Co-authored-by: jgart &lt;jgart@dismail.de&gt;
</span></span></td><td>Zhu Zihao</td></tr>
<tr><td><span title='2023-07-01 16:04:29 +0200'>2023-07-01</span></td><td><a href='/guix/commit/gnu/packages/patches/nix-dont-build-html-doc.diff?id=f3e9dfc5473b5ba7f8d860b2096b56f07d932236'>Revert "gnu: nix: Update to 2.16.0."</a><span class='msg-avail'>...<span class='msg-tooltip'>This reverts commit 554d46882bc4443dcebbba5aac70b016537d0975.

Wrong patch revision.
</span></span></td><td>Nicolas Goaziou</td></tr>
<tr><td><span title='2023-07-01 15:48:55 +0200'>2023-07-01</span></td><td><a href='/guix/commit/gnu/packages/patches/nix-dont-build-html-doc.diff?id=554d46882bc4443dcebbba5aac70b016537d0975'>gnu: nix: Update to 2.16.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/package-management.scm (nix): Update to 2.16.0.
[inputs]: Add nlohmann-json.
[native-inputs]: Add rapidcheck.
[arguments]&lt;#:phases&gt;: In phase "check", change the value of environment
variable  "NIX_STORE" to "/nix/store" temporarily.

* gnu/packages/patches/nix-dont-build-html-doc.diff: Update.

Signed-off-by: Nicolas Goaziou &lt;mail@nicolasgoaziou.fr&gt;
</span></span></td><td>Zhu Zihao</td></tr>