+// FIXME: Portability.
+static void setThreadBackgroundPriority() {
+#ifdef __APPLE__
+ setpriority(PRIO_DARWIN_THREAD, 0, PRIO_DARWIN_BG);
+#endif
+}
+
+static bool hasThreadBackgroundPriority() {
+#ifdef __APPLE__
+ return getpriority(PRIO_DARWIN_THREAD, 0) == 1;
+#else
+ return false;
+#endif
+}