fix rust error "missing unwind resume"

- add test code to demo issue
- disable landing pad creation on build in Makefile

Makefile

@@ -33,7 +33,7 @@ $(kernel): cargo $(rust_os) $(assembly_object_files) $(linker_script)
 	@ld -n --gc-sections -T $(linker_script) -o $(kernel) $(assembly_object_files) $(rust_os)
 
 cargo:
-	@cargo build --target $(target)
+	@cargo rustc --target $(target) -- -Z no-landing-pads
 
 build/arch/$(arch)/%.o: src/arch/$(arch)/%.asm
 	@mkdir -p $(shell dirname $@)

src/lib.rs

@@ -7,6 +7,7 @@ extern crate rlibc;
 #[no_mangle]
 pub extern fn rust_main() {
   let v = ["huge", "page", "long", "mode"];
+  let test = (0..3).flat_map(|x| 0..x).zip(0..);
 }
 
 #[lang = "eh_personality"] extern fn eh_personality() {}