diff --git a/lxsys.c.orig b/lxsys.c
index 1ab89ba..bae667c 100644
--- lxsys.c.orig
+++ lxsys.c
@@ -24,6 +24,7 @@
 #if DARWIN == 1
 #include <mach/machine.h>
 #include <sys/dtrace.h>
+#include <AvailabilityMacros.h>
 #define TRUE_BSD FALSE
 #else
 #if (defined(__unix__) || defined(unix)) && !defined(USG)
@@ -336,7 +337,17 @@ thread_pid[no]=no;
 thread_pid[no]=syscall(SYS_gettid);
 #else
 uint64_t thread_id;
-pthread_threadid_np(NULL, &thread_id);
+#if MAC_OS_X_VERSION_MAX_ALLOWED < 1060 || defined(__POWERPC__)
+    thread_id = pthread_mach_thread_np(pthread_self());
+#elif MAC_OS_X_VERSION_MIN_REQUIRED < 1060
+    if (&pthread_threadid_np != NULL) {
+        pthread_threadid_np(NULL, &thread_id);
+    } else {
+        thread_id = pthread_mach_thread_np(pthread_self());
+    }
+#else
+    pthread_threadid_np(NULL, &thread_id);
+#endif
 thread_pid[no]=(int)thread_id;
 #endif
 #endif