refactor(lib): remove build script detecting rust >= 1.34

Cargo.toml

@@ -18,7 +18,7 @@ include = [
   "Cargo.toml",
   "LICENSE",
   "src/**/*",
-  "build.rs",
+  #"build.rs",
 ]
 
 [dependencies]
@@ -47,9 +47,6 @@ tokio-threadpool = { git = "https://github.com/tokio-rs/tokio", optional = true
 tokio-timer = { git = "https://github.com/tokio-rs/tokio", optional = true }
 want = { git = "https://github.com/seanmonstar/want", branch = "std-future" }
 
-[build-dependencies]
-rustc_version = "0.2"
-
 [dev-dependencies]
 #futures-timer = "0.1"
 num_cpus = "1.0"

build.rs

@@ -1,10 +0,0 @@
-extern crate rustc_version;
-
-use rustc_version::{version, Version};
-
-fn main() {
-    let version = version().unwrap();
-    if version >= Version::parse("1.34.0").unwrap() {
-        println!("cargo:rustc-cfg=try_from");
-    }
-}

src/client/connect/mod.rs

@@ -5,9 +5,9 @@
 //! - A default [`HttpConnector`](HttpConnector) that does DNS resolution and
 //!   establishes connections over TCP.
 //! - The [`Connect`](Connect) trait and related types to build custom connectors.
+use std::convert::TryFrom;
 use std::error::Error as StdError;
 use std::{fmt, mem};
-#[cfg(try_from)] use std::convert::TryFrom;
 
 use bytes::{BufMut, Bytes, BytesMut};
 use ::http::{uri, Response, Uri};
@@ -253,7 +253,6 @@ impl Destination {
     */
 }
 
-#[cfg(try_from)]
 impl TryFrom<Uri> for Destination {
     type Error = crate::error::Error;
 
@@ -538,15 +537,13 @@ mod tests {
         assert_eq!(dst.port(), None);
     }
 
-    #[cfg(try_from)]
     #[test]
     fn test_try_from_destination() {
         let uri: http::Uri = "http://hyper.rs".parse().expect("initial parse");
         let result = Destination::try_from(uri);
         assert_eq!(result.is_ok(), true);
     }
-    
-    #[cfg(try_from)]    
+
     #[test]
     fn test_try_from_no_scheme() {
         let uri: http::Uri = "hyper.rs".parse().expect("initial parse error");