+// Symbols that are extern, but private to the RTS, are declared
+// with visibility "hidden" to hide them outside the RTS shared
+// library.
+#if defined(HAS_VISIBILITY_HIDDEN)
+#define RTS_PRIVATE GNUC3_ATTRIBUTE(visibility("hidden"))
+#else
+#define RTS_PRIVATE /* disabled: RTS_PRIVATE */
+#endif
+
+#if __GNUC__ >= 4
+#define RTS_UNLIKELY(p) __builtin_expect((p),0)
+#else
+#define RTS_UNLIKELY(p) p
+#endif
+