kexectools: fix build on i686

https://hydra.nixos.org/build/99957229
See: https://src.fedoraproject.org/rpms/kexec-tools/c/cb1e5463b5298b064e9b6c86ad6fe3505fec9298

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

@@ -1,4 +1,4 @@
-{ stdenv, buildPackages, fetchurl, zlib }:
+{ stdenv, buildPackages, fetchurl, zlib, fetchpatch }:
 
 stdenv.mkDerivation rec {
   pname = "kexec-tools";
@@ -18,6 +18,16 @@ stdenv.mkDerivation rec {
   depsBuildBuild = [ buildPackages.stdenv.cc ];
   buildInputs = [ zlib ];
 
+  patches = [
+    # fix build on i686
+    # See: https://src.fedoraproject.org/rpms/kexec-tools/c/cb1e5463b5298b064e9b6c86ad6fe3505fec9298
+    (fetchpatch {
+      name = "kexec-tools-2.0.20-fix-broken-multiboot2-buliding-for-i386.patch";
+      url = "https://src.fedoraproject.org/rpms/kexec-tools/raw/cb1e5463b5298b064e9b6c86ad6fe3505fec9298/f/kexec-tools-2.0.20-fix-broken-multiboot2-buliding-for-i386.patch";
+      sha256 = "1kzmcsbhwfdgxlc5s88ir0n494phww1j16yk0z42x09qlkxxkg0l";
+    })
+  ];
+
   meta = with stdenv.lib; {
     homepage = http://horms.net/projects/kexec/kexec-tools;
     description = "Tools related to the kexec Linux feature";