Index: vendor/libbase/threads.cpp
--- vendor/libbase/threads.cpp.orig
+++ vendor/libbase/threads.cpp
@@ -37,6 +37,8 @@ uint64_t GetThreadId() {
   uint64_t tid;
   pthread_threadid_np(NULL, &tid);
   return tid;
+#elif defined(__OpenBSD__)
+  return (uint64_t)getthrid();
 #elif defined(__linux__)
   return syscall(__NR_gettid);
 #elif defined(_WIN32)