process module not found

[4ncly]

proc-macro2-1.0.43 git:(master) ✗ cargo b --release
Compiling proc-macro2 v1.0.43 (/root/sgx/exp/lib/proc-macro2-1.0.43)
error[E0432]: unresolved imports std::process, std::process
--> build.rs:59:10
|
59 | use std::process::{self, Command};
| ^^^^^^^ ^^^^ no process in the root
| |
| could not find process in std

when i want to move proc-macro2 to Rust SGX, and i find an error in build.rs