Correctly choose DarwinSSL TLS backend on macOS for libcurl.
According to https://curl.haxx.se/docs/install.html, explicitly disabling OpenSSL/BoringSSL/libressl with the confusing --without-ssl flag is necessary.

Also disable a few more unneeded dependencies explicitly.

Patch By: Stan
Accepted By: trompetin17
Differential Revision: https://code.wildfiregames.com/D1687