usestd::env;fnmain(){// Set the `ruma_unstable_exhaustive_types` configuration from an environment variable.
ifenv::var("RUMA_UNSTABLE_EXHAUSTIVE_TYPES").is_ok(){println!("cargo:rustc-cfg=ruma_unstable_exhaustive_types");}println!("cargo:rerun-if-env-changed=RUMA_UNSTABLE_EXHAUSTIVE_TYPES");}