error: extern location for std does not exist: 

error: `#[panic_handler]` function required, but not found

error: language item required, but not found: `eh_personality`
   |
   = note: this can occur when a binary crate with `#![no_std]` is compiled for a target where `eh_personality` is defined in the standard library
   = help: you may be able to compile for a target that doesn't need `eh_personality`, specify a target with `--target` or in `.cargo/config`

error: aborting due to 3 previous errors

