Makefile: add flags and dependencies
Makefile: add flags and dependencies

FrozenCow/gummiboot,freedesktop-unofficial-mirror/gummiboot,aaronp24/gummiboot,todorez/gummiboot-multiboot2,todorez/tummiboot,karelzak/gummiboot,aaronp24/gummiboot,trilean/gummiboot,liliang365/my_gummiboot,FrozenCow/gummiboot,android-ia/platform_external_gummiboot,trilean/gummiboot,todorez/gummiboot-multiboot2,karelzak/gummiboot,freedesktop-unofficial-mirror/gummiboot,android-ia/platform_external_gummiboot,todorez/tummiboot,miguelinux/gummiboot2systemd-boot,miguelinux/gummiboot2systemd-boot,liliang365/my_gummiboot