OpenBSD has two stdc++ libraries: use the newer

stdc++ is from base, and is an old library (GCC 4.2)
estdc++ is from ports, and is a recent library (GCC 4.9 currently)

as LLVM requires the newer version, use it if under OpenBSD.

Author: semarie

src/librustc_llvm/build.rs

@@ -230,18 +230,25 @@ fn main() {
         }
     }
 
+    // OpenBSD has a particular C++ runtime library name
+    let stdcppname = if target.contains("openbsd") {
+        "estdc++"
+    } else {
+        "stdc++"
+    };
+
     // C++ runtime library
     if !target.contains("msvc") {
         if let Some(s) = env::var_os("LLVM_STATIC_STDCPP") {
             assert!(!cxxflags.contains("stdlib=libc++"));
             let path = PathBuf::from(s);
             println!("cargo:rustc-link-search=native={}",
                      path.parent().unwrap().display());
-            println!("cargo:rustc-link-lib=static=stdc++");
+            println!("cargo:rustc-link-lib=static={}", stdcppname);
         } else if cxxflags.contains("stdlib=libc++") {
             println!("cargo:rustc-link-lib=c++");
         } else {
-            println!("cargo:rustc-link-lib=stdc++");
+            println!("cargo:rustc-link-lib={}", stdcppname);
         }
     }
 }