You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cross_compile.rs
    path of file: ./repos/cargo/crates/cargo-test-support/src
    
    the code of the file until where you have to start completion: //! Support for cross-compile tests with the `--target` flag.
//!
//! Note that cross-testing is very limited. You need to install the
//! "alternate" target to the host (32-bit for 64-bit hosts or vice-versa).
//!
//! Set CFG_DISABLE_CROSS_TESTS=1 environment variable to disable these tests
//! if you are unable to use the alternate target. Unfortunately 32-bit
//! support 
    
pub fn alternate() -> &'static str {
    if cfg!(all(target_os = "macos", target_arch = "aarch64")) {
        "x86_64-apple-darwin"
    } else if cfg!(target_os = "macos") {
        "x86_64-apple-ios"
    } else if cfg!(target_os = "linux") {
        "i686-unknown-linux-gnu"
    } else if cfg!(all(target_os = "windows", target_env = "msvc")) {
        "i686-pc-windows-msvc"
    } else if cfg!(all(target_os = "windows", target_env = "gnu")) {
        "i686-pc-windows-gnu"
    } else {
        panic!("This test should be gated on cross_compile::disabled.");
    }
}