Replace --without-libidn with --without-libidn2
Replace --without-libidn with --without-libidn2

Curl uses libidn2, libidn is gone. The --without-libidn has no effect.

I found this while building statically-linked binaries of cargo for
DragonFly (which fails without this option).

alexcrichton/curl-rust,alexcrichton/curl-rust,alexcrichton/curl-rust,carllerche/curl-rust