It seems to support multiple options but requires you pick at least one of them. https://github.com/aws/s2n-tls/blob/main/docs/BUILD.md#building-with-a-specific

It seems to support multiple options but requires you pick at least one of them. https://github.com/aws/s2n-tls/blob/main/docs/BUILD.md#building-with-a-specific-libcrypto https://github.com/aws/s2n-tls/blob/main/docs/BUILD.md#build... AWS-LC is the recommended option of the supported choices, there doesn't seem to be a "built-in" type choice.