问题：如何解决（或修复）我的两个依赖项链接到同一个库但该库不能链接两次的情况？这似乎通常可以通过共享库来解决，但我不确定如何使用 Rust 来解决它。
细节：
我正在使用Nickel 框架和rust-postgres为数据库制作一个 Rust 的 Web 应用程序。构建时出现以下错误：
> cargo build
native library `openssl` is being linked to by more than one package, and can only be linked to by one package
openssl-sys v0.3.3 (https://github.com/sfackler/rust-openssl.git#ee66da60)
openssl-sys v0.3.3
通过 Cargo.lock，openssl 被 http（它是镍的依赖）和 rust-postgres 引用。
我的 Cargo.toml 看起来像这样：
[package]
name = "goodoldweb"
version = "0.0.1"
authors = ["..."]
[dependencies.nickel]
git="https://github.com/nickel-org/nickel.rs.git"
[dependencies.postgres]
git="https://github.com/sfackler/rust-postgres.git"
这是完整的 Cargo.lock：
[root]
name = "goodoldweb"
version = "0.0.1"
dependencies = [
"nickel 0.1.0 (git+https://github.com/nickel-org/nickel.rs.git)",
"postgres 0.6.1 (git+https://github.com/sfackler/rust-postgres.git)",
]
[[package]]
name = "byteorder"
version = "0.2.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "gcc"
version = "0.1.7"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "groupable"
version = "0.1.0"
source = "git+https://github.com/nickel-org/groupable-rs#efc8d769f611558f086322cd8d2d5ff53314e435"
[[package]]
name = "http"
version = "0.1.0-pre"
source = "git+https://github.com/nickel-org/rust-http.git#1997192b7662ee5bf3bf381bfd9e2aa70f85a545"
dependencies = [
"openssl 0.3.3 (git+https://github.com/sfackler/rust-openssl.git)",
"time 0.1.17 (git+https://github.com/rust-lang/time)",
"url 0.2.18 (git+https://github.com/nickel-org/rust-url.git)",
]
[[package]]
name = "libc"
version = "0.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "libressl-pnacl-sys"
version = "2.1.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"pnacl-build-helper 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "log"
version = "0.2.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "matches"
version = "0.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "nickel"
version = "0.1.0"
source = "git+https://github.com/nickel-org/nickel.rs.git#8c2e6a9bdbce0a3ec53d559b86f5060ee1ea6c29"
dependencies = [
"groupable 0.1.0 (git+https://github.com/nickel-org/groupable-rs)",
"http 0.1.0-pre (git+https://github.com/nickel-org/rust-http.git)",
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
"nickel_macros 0.0.1 (git+https://github.com/nickel-org/nickel.rs.git)",
"plugin 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
"regex 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
"regex_macros 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
"rust-mustache 0.3.0 (git+https://github.com/nickel-org/rust-mustache.git)",
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
"time 0.1.17 (git+https://github.com/rust-lang/time)",
"typemap 0.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
"url 0.2.18 (git+https://github.com/nickel-org/rust-url.git)",
]
[[package]]
name = "nickel_macros"
version = "0.0.1"
source = "git+https://github.com/nickel-org/nickel.rs.git#8c2e6a9bdbce0a3ec53d559b86f5060ee1ea6c29"
[[package]]
name = "openssl"
version = "0.3.3"
source = "git+https://github.com/sfackler/rust-openssl.git#ee66da6060c57bc86906261ee3d684fac1fd05e4"
dependencies = [
"openssl-sys 0.3.3 (git+https://github.com/sfackler/rust-openssl.git)",
]
[[package]]
name = "openssl"
version = "0.3.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"openssl-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "openssl-sys"
version = "0.3.3"
source = "git+https://github.com/sfackler/rust-openssl.git#ee66da6060c57bc86906261ee3d684fac1fd05e4"
dependencies = [
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
"libressl-pnacl-sys 2.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
"pkg-config 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "openssl-sys"
version = "0.3.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
"libressl-pnacl-sys 2.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
"pkg-config 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "phantom"
version = "0.0.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "phf"
version = "0.6.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"phf_shared 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "phf_macros"
version = "0.6.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"phf_shared 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
"rand 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "phf_shared"
version = "0.6.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "pkg-config"
version = "0.2.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "plugin"
version = "0.2.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"typemap 0.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "pnacl-build-helper"
version = "1.3.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "postgres"
version = "0.6.1"
source = "git+https://github.com/sfackler/rust-postgres.git#fe6ae0c63a6e5d66d2afb785605b7d89ec47062d"
dependencies = [
"byteorder 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
"openssl 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
"phf 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
"phf_macros 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
"time 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "rand"
version = "0.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"libc 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "regex"
version = "0.1.14"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "regex_macros"
version = "0.1.8"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"regex 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "rust-mustache"
version = "0.3.0"
source = "git+https://github.com/nickel-org/rust-mustache.git#58ed857c88f8e5230913c382034601f37141b4ee"
dependencies = [
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "rustc-serialize"
version = "0.2.12"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "time"
version = "0.1.17"
source = "git+https://github.com/rust-lang/time#0960d5e21b332088b04f62117514b0a02fd31259"
dependencies = [
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
"libc 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "time"
version = "0.1.17"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
"libc 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "typemap"
version = "0.0.8"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"phantom 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
"unsafe-any 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "unsafe-any"
version = "0.2.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "url"
version = "0.2.18"
source = "git+https://github.com/nickel-org/rust-url.git#5801582b307c16f759b5fe11dec71385af86180c"
dependencies = [
"matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
]