this warning should not occur: warning: be sure to add `/var/tmp/portage/sys-apps/lsd-0.15.1/image/usr/bin` to your PATH to be able to run the installed binaries
cargo just checks if $DESTDIR/bin is in path and prints reminder for users of standaline cargo to add whatever they are installing into to $PATH since nothing we can do about it, as adding temporary destination to $PATH is bad idea. it's impossible to turn this check off, also it's absolutely harmless. https://github.com/rust-lang/cargo/blob/545f354259be4e9745ea00a524c0e4c51df01aa6/src/cargo/ops/cargo_install.rs#L109-L118
