use pthread_getspecific instead of __thread

skynet-src/skynet_imp.h

@@ -12,6 +12,12 @@ struct skynet_config {
 	const char * standalone;
 };
 
+#define THREAD_WORKER 0
+#define THREAD_MAIN 1
+#define THREAD_SOCKET 2
+#define THREAD_TIMER 3
+#define THREAD_MONITOR 4
+
 void skynet_start(struct skynet_config * config);
 
 #endif