Add x86_64 linux configuration

This adds the config required to build an EFI executable with inbuilt
initramfs on x86_64 systems.

pkgs/boot/linux/build

@@ -1,5 +1,8 @@
 
-install_target="zinstall modules_install dtbs_install"
+case "$ARCH" in
+  amd64) install_target="install modules_install" ;;
+  arm64) install_target="zinstall modules_instlal dtbs_install" ;;
+esac
 type=make
 
 pre_build() {
@@ -16,13 +19,23 @@ pre_build() {
 
   if ! test -f .config
   then
-    cp ../config .config
+    cp ../config.${ARCH} .config
   fi
 }
 
 post_build() {
-  mkdir -p ${BOOTPART}/boot
-  cp ${INSTALL_PATH}/vmlinuz* ${BOOTPART}/boot/kernel8.img
-  cp -r ${BUILD_DIR}/lib/modules ${BOOTPART}/boot/
-  find ${INSTALL_PATH} -name '*.dtb' | xargs -I{} cp {} ${BOOTPART}/boot/
+  mkdir -p ${DATAPART}
+  cp -r ${BUILD_DIR}/lib/modules ${DATAPART}/
+
+  case "$ARCH" in
+    x86_64)
+      mkdir -p ${BOOTPART}/EFI/Boot
+      cp ${INSTALL_PATH}/vmlinuz ${BOOTPART}/EFI/Boot/Bootx64.efi
+      ;;
+    arm64)
+      mkdir -p ${BOOTPART}/boot
+      cp ${INSTALL_PATH}/vmlinuz* ${BOOTPART}/boot/kernel8.img
+      find ${INSTALL_PATH} -name '*.dtb' | xargs -I{} cp {} ${BOOTPART}/boot/
+      ;;
+  esac
 }