Replace env!("...") expressions am: 1697204ac1 am: 63812f870f am: e3c3d2f49a

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/protobuf-codegen/+/1484999

Change-Id: I66ac9645f1160c2c84bddd7cd3f554373e4c6397