lib: add gzip support to hwImage, novaImage

lib/default.nix

@@ -39,7 +39,9 @@ in rec {
         > $out/config.dhall.bin
     '';
 
-  hwImage = coreLinkAddr: bootstrapLinkAddr: basePkg: name: env: boot:
+  hwImage = coreLinkAddr: bootstrapLinkAddr: basePkg: name:
+    { gzip ? false, ... }@env:
+    boot:
     nixpkgs.stdenv.mkDerivation {
       name = name + "-hw-image";
       build = compileBoot name env boot;
@@ -94,10 +96,12 @@ in rec {
           bootstrap/modules_asm \
           ${bootstrapLinkAddr} \
           $out/image.elf
-      '';
+      '' + nixpkgs.lib.optionalString gzip "gzip $out/image.elf";
     };
 
-  novaImage = name: env: boot:
+  novaImage = name:
+    { gzip ? false, ... }@env:
+    boot:
     nixpkgs.stdenv.mkDerivation {
       name = name + "-nova-image";
       build = compileBoot name env boot;
@@ -117,7 +121,7 @@ in rec {
         	-Ttext=0x100000 -gc-sections \
         	"${testPkgs.base-nova.coreObj}" boot_modules.o \
         	-o $out/image.elf
-      '';
+      '' + nixpkgs.lib.optionalString gzip "gzip $out/image.elf";
     };
 
   mergeManifests = inputs: