Index: lib/lsan/lsan_interceptors.cc
===================================================================
--- lib/lsan/lsan_interceptors.cc
+++ lib/lsan/lsan_interceptors.cc
@@ -53,6 +53,12 @@
   struct nothrow_t;
 }
 
+#if SANITIZER_LINUX || SANITIZER_FREEBSD
+#define PTHREAD_CREATE_DETACHED 1
+#elif SANITIZER_MAC
+#define PTHREAD_CREATE_DETACHED 2
+#endif
+
 INTERCEPTOR(void*, malloc, uptr size) {
   ENSURE_LSAN_INITED;
   GET_STACK_TRACE_MALLOC;
@@ -290,7 +296,8 @@
     res = REAL(pthread_create)(th, attr, __lsan_thread_start_func, &p);
   }
   if (res == 0) {
-    int tid = ThreadCreate(GetCurrentThread(), *(uptr *)th, detached);
+    int tid = ThreadCreate(GetCurrentThread(), *(uptr *)th,
+                           detached == PTHREAD_CREATE_DETACHED);
     CHECK_NE(tid, 0);
     atomic_store(&p.tid, tid, memory_order_release);
     while (atomic_load(&p.tid, memory_order_acquire) != 0)