:feat: support compile with lower glibc version

Author: libinyl

test/test.cpp

@@ -5,6 +5,12 @@
  */ 
 #include "../code/log/log.h"
 #include "../code/pool/threadpool.h"
+#include <features.h>
+
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
+#include <sys/syscall.h>
+#define gettid() syscall(SYS_gettid)
+#endif
 
 void TestLog() {
     int cnt = 0, level = 0;