pub fn warning(message: &str)
Expand description
The warning
instruction tells Cargo to display a warning after the build
script has finished running. Warnings are only shown for path dependencies
(that is, those you’re working on locally), so for example warnings printed
out in crates.io crates are not emitted by default. The -vv
“very verbose”
flag may be used to have Cargo display warnings for all crates.