add zImage output

modules/outputs.nix

@@ -30,6 +30,16 @@ in
           Kernel vmlinux file (usually ELF)
         '';
       };
+      zimage = mkOption {
+        type = types.package;
+        internal = true;
+        description = ''
+          zimage
+          ******
+
+          Kernel in compressed self-extracting package
+        '';
+      };
       dtb = mkOption {
         type = types.package;
         internal  = true;
@@ -80,6 +90,10 @@ in
       kernel = liminix.builders.kernel.override {
         inherit (config.kernel) config src extraPatchPhase;
       };
+      zimage = liminix.builders.kernel.override {
+        targets = ["arch/arm/boot/zImage"];
+        inherit (config.kernel) config src extraPatchPhase;
+      };
       dtb = liminix.builders.dtb {
         inherit (config.boot) commandLine;
         dts = config.hardware.dts.src;

pkgs/kernel/default.nix

@@ -7,6 +7,7 @@
  , config
  , src
  , extraPatchPhase ? "echo"
+ , targets ? ["vmlinux"]
 } :
 let
   writeConfig = import ./write-kconfig.nix { inherit lib writeText; };
@@ -90,12 +91,12 @@ stdenv.mkDerivation rec {
   '';
 
   buildPhase = ''
-    make vmlinux modules_prepare -j$NIX_BUILD_CORES
+    make ${lib.concatStringsSep " " (map baseNameOf targets)} modules_prepare -j$NIX_BUILD_CORES
   '';
 
   installPhase = ''
     ${CROSS_COMPILE}strip -d vmlinux
-    cp vmlinux $out
+    cp ${lib.concatStringsSep " " targets} $out
     mkdir -p $headers
     cp -a include .config $headers/
     mkdir -p $modulesupport