Remove linking unless explicitly enabling testing

.travis.yml

@@ -25,15 +25,16 @@ matrix:
 
 before_install:
 - |
+  rvm get stable
   rvm install "$BUILD_RUBY_VERSION"
   rvm use "$BUILD_RUBY_VERSION"
   ruby --version
   ruby -e 'require "pp"; pp RbConfig::CONFIG'
 
 before_script:
-- |
-  pip install 'travis-cargo<0.2' --user &&
-  export PATH=$HOME/Library/Python/2.7/bin:$HOME/.local/bin:$PATH
+- if [ "$TRAVIS_OS_NAME" == "linux" ]; then pip install 'travis-cargo<0.2' --user; fi
+- if [ "$TRAVIS_OS_NAME" == "osx" ]; then pip2 install 'travis-cargo<0.2' --user; fi
+- export PATH=$HOME/Library/Python/2.7/bin:$HOME/.local/bin:$PATH
 
 script:
 - |
@@ -45,8 +46,4 @@ env:
     - TRAVIS_CARGO_NIGHTLY_FEATURE=""
   matrix:
     - BUILD_RUBY_VERSION: 2.3.5
-    - BUILD_RUBY_VERSION: 2.3.5
-      RUBY_STATIC: 1
-    - BUILD_RUBY_VERSION: 2.4.2
     - BUILD_RUBY_VERSION: 2.4.2
-      RUBY_STATIC: 1

Cargo.toml

@@ -19,3 +19,4 @@ libc = "0.2.0"
 [features]
 default = []
 unstable = []
+test = []

build.rs

@@ -16,39 +16,9 @@ fn rbconfig(key: &str) -> String {
     String::from_utf8(config.stdout).expect("RbConfig value not UTF-8!")
 }
 
-fn use_libdir() {
-    println!("cargo:rustc-link-search={}", rbconfig("libdir"));
-}
-
-fn transform_lib_args(rbconfig_key: &str, replacement: &str) -> String {
-    rbconfig(rbconfig_key).replace("-l", replacement)
-}
-
-fn use_static() {
-    // Ruby gives back the libs in the form: `-lpthread -lgmp`
-    // Cargo wants them as: `-l pthread -l gmp`
-    println!("cargo:rustc-flags={}", transform_lib_args("LIBS", "-l "));
-}
-
-fn use_dylib() {
-    use_libdir();
-    println!("cargo:rustc-link-lib=dylib={}", rbconfig("RUBY_SO_NAME"));
-}
-
 fn main() {
-    if rbconfig("target_os") != "mingw32" && env::var_os("RUBY_STATIC").is_some() {
-        use_static()
-    } else {
-        match rbconfig("ENABLE_SHARED").as_str() {
-            "no" => use_static(),
-            "yes" => use_dylib(),
-            _ => {
-                let msg = "Error! Couldn't find a valid value for \
-                RbConfig::CONFIG['ENABLE_SHARED']. \
-                This may mean that your ruby's build config is corrupted. \
-                Possible solution: build a new Ruby with the `--enable-shared` configure opt.";
-                panic!(msg)
-            }
-        }
+    if cfg!(feature="test") {
+        println!("cargo:rustc-link-search={}", rbconfig("libdir"));
+        println!("cargo:rustc-link-lib=dylib={}", rbconfig("RUBY_SO_NAME"));
     }
 }