Configuration The file .cargo/config.toml is used to specify conditional compile options that are passed to the rustc --cfg command
gpopt_trail="santa_fe" | "los_altos"
Default: "santa_fe"
Example contents for .cargo/config.toml
[build] #rustflags = "--cfg gpopt_trail="santa_fe"" rustflags = "--cfg gpopt_trail="los_altos""
Building $ cargo build [--verbose]
Running $ cargo run