Run thread-local-extern-static test only on supported platforms.

Author: mneumann

src/test/auxiliary/thread-local-extern-static.rs

@@ -9,8 +9,9 @@
 // except according to those terms.
 
 #![feature(thread_local)]
+#![feature(cfg_target_thread_local)]
 #![crate_type = "lib"]
 
 #[no_mangle]
-#[thread_local]
+#[cfg_attr(target_thread_local, thread_local)]
 pub static FOO: u32 = 3;

src/test/run-pass/thread-local-extern-static.rs

@@ -11,11 +11,12 @@
 // aux-build:thread-local-extern-static.rs
 
 #![feature(thread_local)]
+#![feature(cfg_target_thread_local)]
 
 extern crate thread_local_extern_static;
 
 extern {
-    #[thread_local]
+    #[cfg_attr(target_thread_local, thread_local)]
     static FOO: u32;
 }