libssh2-sys: add `vendored-openssl` feature to build openssl-src

This enables building `ssh2` and `libssh2-sys` with the
`vendored-openssl` feature, which in turn causes openssl to be built and
linked locally, and does not require that homebrew or some other
externally provided version of openssl be made available.

It does require a working C compiler, perl and make.

1 files changed, 3 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index d10e542..8745af2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,6 +13,9 @@ Bindings to libssh2 for interacting with SSH servers and executing remote
 commands, forwarding local ports, etc.
 """
 
+[features]
+vendored-openssl = ["libssh2-sys/vendored-openssl"]
+
 [dependencies]
 bitflags = "1.0.4"
 libc = "0.2"