syslinux: make reproducible

pkgs/os-specific/linux/syslinux/default.nix

···
       url = mkURL "fa1349f1" "0002-gfxboot-menu-label.patch";
       sha256 = "06ifgzbpjj4picpj17zgprsfi501zf4pp85qjjgn29i5rs291zni";
     })
-    (fetchpatch {
-      url = "https://git.archlinux.org/svntogit/packages.git/plain/trunk/0005-gnu-efi-version-compatibility.patch?h=packages/syslinux";
-      sha256 = "0fbqz56hj8az8ws26m39hyp3l5fvcbzvzdddqz3x6n56hzdpz1p6";
+    (fetchurl {
+      url = "https://git.archlinux.org/svntogit/packages.git/plain/trunk/0005-gnu-efi-version-compatibility.patch?id=821c3da473d1399d930d5b4a086e46a4179eaa45";
+      name = "0005-gnu-efi-version-compatibility.patch";
+      sha256 = "1mz2idg8cwn0mvd3jixxynhkn7rhmi5fp8cc8zznh5f0ysfra446";
+    })
+    (fetchurl {
+      url = "https://git.archlinux.org/svntogit/packages.git/plain/trunk/0025-reproducible-build.patch?id=821c3da473d1399d930d5b4a086e46a4179eaa45";
+      name = "0025-reproducible-build.patch";
+      sha256 = "0qk6wc6z3648828y3961pn4pi7xhd20a6fqn6z1mnj22bbvzcxls";
     })
     (fetchurl {
       # mbr.bin: too big (452 > 440)
···
     "DATADIR=$(out)/share"
     "MANDIR=$(out)/share/man"
     "PERL=perl"
+    "HEXDATE=0x00000000"
   ]
     ++ stdenv.lib.optionals stdenv.hostPlatform.isi686 [ "bios" "efi32" ];