Fix some waterboxhost warnings

🤞that this is correct

waterbox/waterboxhost/src/cinterface.rs

@@ -169,7 +169,7 @@ pub extern fn wbx_create_host(layout: &MemoryLayoutTemplate, module_name: *const
 pub extern fn wbx_destroy_host(obj: *mut WaterboxHost, ret: &mut Return<()>) {
 	let res = (|| {
 		unsafe {
-			Box::from_raw(obj);
+			drop(Box::from_raw(obj));
 			Ok(())
 		}
 	})();

waterbox/waterboxhost/src/gdb.rs

@@ -90,5 +90,5 @@ pub unsafe fn deregister(data: &[u8]) {
 	__jit_debug_descriptor.action_flag = JIT_UNREGISTER_FN;
 	__jit_debug_register_code();
 
-	Box::from_raw(entry);
+	drop(Box::from_raw(entry));
 }

waterbox/waterboxhost/src/lib.rs

@@ -4,7 +4,6 @@
 #![feature(never_type)]
 #![feature(control_flow_enum)]
 #![feature(core_intrinsics)]
-#![feature(map_first_last)]
 
 #![allow(dead_code)]