rt: Fix build with clang on non-Mac

Author: lht

src/rt/rust_unwind.h

@@ -6,9 +6,7 @@
 #ifdef __APPLE__
 #include <libunwind.h>
 
-typedef int _Unwind_Action;
 typedef void _Unwind_Context;
-typedef void _Unwind_Exception;
 typedef int _Unwind_Reason_Code;
 
 #else
@@ -17,5 +15,12 @@ typedef int _Unwind_Reason_Code;
 
 #endif
 
+#if (defined __APPLE__) || (defined __clang__)
+
+typedef int _Unwind_Action;
+typedef void _Unwind_Exception;
+
+#endif
+
 #endif