The basic idea here is that there is a feature for each supported
OpenSSL version. Enabling multiple features represents support for
multiple OpenSSL versions, but it's then up to you to check which
version you link against (probably by depending on openssl-sys and
making a build script similar to what openssl does).
This commit is relatively major refactoring of the `openssl-sys` crate as well
as the `openssl` crate itself. The end goal here was to support OpenSSL 1.1.0,
and lots of other various tweaks happened along the way. The major new features
are:
* OpenSSL 1.1.0 is supported
* OpenSSL 0.9.8 is no longer supported (aka all OSX users by default)
* All FFI bindings are verified with the `ctest` crate (same way as the `libc`
crate)
* CI matrixes are vastly expanded to include 32/64 of all platforms, more
OpenSSL version coverage, as well as ARM coverage on Linux
* The `c_helpers` module is completely removed along with the `gcc` dependency.
* The `openssl-sys` build script was completely rewritten
* Now uses `OPENSSL_DIR` to find the installation, not include/lib env vars.
* Better error messages for mismatched versions.
* Better error messages for failing to find OpenSSL on a platform (more can be
done here)
* Probing of OpenSSL build-time configuration to inform the API of the `*-sys`
crate.
* Many Cargo features have been removed as they're now enabled by default.
As this is a breaking change to both the `openssl` and `openssl-sys` crates this
will necessitate a major version bump of both. There's still a few more API
questions remaining but let's hash that out on a PR!
Closes#452
Ivan Nikulin