discord-rs: Fails to build on Arch Linux due to system openssl 1.1.0

The Rust crate OpenSSL 0.7.4 (which is what discord-rs transitively resolves to) fails to build with openssl 1.1.0, which is what is on Arch Linux right now. This makes discord-rs completely unusable.

This issue can be resolved by upgrading all dependencies such that a higher version of the Rust openssl crate is used (the current version is 0.9.12). However, in local testing, cloning discord-rs and doing a simple upgrade of everything to their most recent versions, causes many incompatibilities - mostly around websocket, I believe related to #99.

Here’s the build log:

   Compiling openssl v0.7.14
   Compiling openssl-sys-extras v0.7.14
error: failed to run custom build command for `openssl v0.7.14`
process didn't exit successfully: `/home/khyperia/me/weechat-discord/target/debug/build/openssl-f2d87cfdc2e2aa2f/build-script-build` (exit code: 101)
--- stdout
TARGET = Some("x86_64-unknown-linux-gnu")
OPT_LEVEL = Some("0")
TARGET = Some("x86_64-unknown-linux-gnu")
HOST = Some("x86_64-unknown-linux-gnu")
TARGET = Some("x86_64-unknown-linux-gnu")
TARGET = Some("x86_64-unknown-linux-gnu")
HOST = Some("x86_64-unknown-linux-gnu")
CC_x86_64-unknown-linux-gnu = None
CC_x86_64_unknown_linux_gnu = None
HOST_CC = None
CC = None
HOST = Some("x86_64-unknown-linux-gnu")
TARGET = Some("x86_64-unknown-linux-gnu")
HOST = Some("x86_64-unknown-linux-gnu")
CFLAGS_x86_64-unknown-linux-gnu = None
CFLAGS_x86_64_unknown_linux_gnu = None
HOST_CFLAGS = None
CFLAGS = None
PROFILE = Some("debug")
running: "cc" "-O0" "-ffunction-sections" "-fdata-sections" "-fPIC" "-g" "-m64" "-o" "/home/khyperia/me/weechat-discord/target/debug/build/openssl-1d3ea894fa03cc5a/out/src/c_helpers.o" "-c" "src/c_helpers.c"
cargo:warning=src/c_helpers.c: In function ‘rust_SSL_clone’:
cargo:warning=src/c_helpers.c:4:5: warning: implicit declaration of function ‘CRYPTO_add’ [-Wimplicit-function-declaration]
cargo:warning=     CRYPTO_add(&ssl->references, 1, CRYPTO_LOCK_SSL);
cargo:warning=     ^~~~~~~~~~
cargo:warning=src/c_helpers.c:4:20: error: dereferencing pointer to incomplete type ‘SSL {aka struct ssl_st}’
cargo:warning=     CRYPTO_add(&ssl->references, 1, CRYPTO_LOCK_SSL);
cargo:warning=                    ^~
cargo:warning=src/c_helpers.c:4:37: error: ‘CRYPTO_LOCK_SSL’ undeclared (first use in this function)
cargo:warning=     CRYPTO_add(&ssl->references, 1, CRYPTO_LOCK_SSL);
cargo:warning=                                     ^~~~~~~~~~~~~~~
cargo:warning=src/c_helpers.c:4:37: note: each undeclared identifier is reported only once for each function it appears in
cargo:warning=src/c_helpers.c: In function ‘rust_SSL_CTX_clone’:
cargo:warning=src/c_helpers.c:8:20: error: dereferencing pointer to incomplete type ‘SSL_CTX {aka struct ssl_ctx_st}’
cargo:warning=     CRYPTO_add(&ctx->references,1,CRYPTO_LOCK_SSL_CTX);
cargo:warning=                    ^~
cargo:warning=src/c_helpers.c:8:35: error: ‘CRYPTO_LOCK_SSL_CTX’ undeclared (first use in this function)
cargo:warning=     CRYPTO_add(&ctx->references,1,CRYPTO_LOCK_SSL_CTX);
cargo:warning=                                   ^~~~~~~~~~~~~~~~~~~
cargo:warning=src/c_helpers.c: In function ‘rust_X509_clone’:
cargo:warning=src/c_helpers.c:12:21: error: dereferencing pointer to incomplete type ‘X509 {aka struct x509_st}’
cargo:warning=     CRYPTO_add(&x509->references,1,CRYPTO_LOCK_X509);
cargo:warning=                     ^~
cargo:warning=src/c_helpers.c:12:36: error: ‘CRYPTO_LOCK_X509’ undeclared (first use in this function)
cargo:warning=     CRYPTO_add(&x509->references,1,CRYPTO_LOCK_X509);
cargo:warning=                                    ^~~~~~~~~~~~~~~~
exit code: 1
command did not execute successfully, got: exit code: 1
--- stderr
thread 'main' panicked at 'explicit panic', /home/khyperia/data/cargo/registry/src/github.com-1ecc6299db9ec823/gcc-0.3.49/src/lib.rs:1210
note: Run with `RUST_BACKTRACE=1` for a backtrace.
Build failed, waiting for other jobs to finish...
error: build failed