`openssl-src-rs` use `SDKs` as separator for iOS SDK root path, [panic lines](https://github.com/alexcrichton/openssl-src-rs/blob/6d6109f39d7bbe564f1f5e1327011fca58f1d117/src/lib.rs#L536-L538). `cross-rs` use `SDK` directory to store iOS SDK, [ref](https://github.com/cross-rs/cross-toolchains/blob/main/docker/ios.sh#L61). A path example: ``` /opt/cctools/SDK/iPhoneOS11.3.sdk ``` Should we improve the processing of SDK paths?