fn main() {
let families: Vec<_> = std::env::vars().filter_map(|(key, _value)| {
if key.starts_with("CARGO_FEATURE_STM32") {
Some(key[14..].to_ascii_lowercase()) // Strip 'CARGO_FEATURE_'
} else {
None
}
}).collect();
if families.is_empty() {
println!("No family features selected");
std::process::exit(1);
}
if families.len() > 1 {
println!("More than one family feature selected: {:?}", families);
std::process::exit(1);
}
}