Curl depends on external libraries for some features (and libcurl for all features). You can build curl without them, but curl gets a lot better if you have a few of these libraries:
| Library | Used for... |
|---|---|
| OpenSSL | TLS (https) support |
| zlib | The automatic "deflate" decompression |
| OpenLDAP | LDAP support |
| mbed TLS | TLS (https) support |
| heimdal | Support for GSS-API can be provided by the heimdal package and is used to for provide the Kerberos and SPNEGO authentication in libcurl. |
| MIT Kerberos | The MIT Kerberos package is also a GSS-API library which can be used to provide support for the Kerberos and SPNEGO authentication in libcurl. |
| nghttp2 | For http2 support. |
| c-ares | For asynchronous name resolves. |
| libidn | For performing the proper IDNA encodings for international domain names to work. |
| GnuTLS | TLS (https) support. |
| NSS | TLS (https) support. |
| wolfSSL | TLS (https) support. |
| libssh2 | For SCP and SFTP support. |