Factor out a helper for the getting C runtime linkage

This commit makes no functional changes.

Author: smaeul

src/librustc/session/mod.rs

@@ -429,6 +429,22 @@ impl Session {
             .unwrap_or(self.opts.debug_assertions)
     }
 
+    pub fn crt_static(&self) -> bool {
+        let requested_features = self.opts.cg.target_feature.split(',');
+        let found_negative = requested_features.clone().any(|r| r == "-crt-static");
+        let found_positive = requested_features.clone().any(|r| r == "+crt-static");
+
+        // If the target we're compiling for requests a static crt by default,
+        // then see if the `-crt-static` feature was passed to disable that.
+        // Otherwise if we don't have a static crt by default then see if the
+        // `+crt-static` feature was passed.
+        if self.target.target.options.crt_static_default {
+            !found_negative
+        } else {
+            found_positive
+        }
+    }
+
     pub fn must_not_eliminate_frame_pointers(&self) -> bool {
         self.opts.debuginfo != DebugInfoLevel::NoDebugInfo ||
         !self.target.target.options.eliminate_frame_pointer

src/librustc_driver/target_features.rs

@@ -25,21 +25,7 @@ pub fn add_configuration(cfg: &mut ast::CrateConfig, sess: &Session) {
         cfg.insert((tf, Some(feat)));
     }
 
-    let requested_features = sess.opts.cg.target_feature.split(',');
-    let found_negative = requested_features.clone().any(|r| r == "-crt-static");
-    let found_positive = requested_features.clone().any(|r| r == "+crt-static");
-
-    // If the target we're compiling for requests a static crt by default,
-    // then see if the `-crt-static` feature was passed to disable that.
-    // Otherwise if we don't have a static crt by default then see if the
-    // `+crt-static` feature was passed.
-    let crt_static = if sess.target.target.options.crt_static_default {
-        !found_negative
-    } else {
-        found_positive
-    };
-
-    if crt_static {
+    if sess.crt_static() {
         cfg.insert((tf, Some(Symbol::intern("crt-static"))));
     }
 }