[sanitizer] Fix test linking

GitOrigin-RevId: afafa883a4757d88d869d1abb6bf7e11022fd521
diff --git a/test/sanitizer_common/TestCases/Linux/pthread_mutex.cpp b/test/sanitizer_common/TestCases/Linux/pthread_mutex.cpp
index 6109581..2882942 100644
--- a/test/sanitizer_common/TestCases/Linux/pthread_mutex.cpp
+++ b/test/sanitizer_common/TestCases/Linux/pthread_mutex.cpp
@@ -1,5 +1,5 @@
-// RUN: %clangxx -O1 %s -o %t && %run %t
-// RUN: %clangxx -O1 -DUSE_GLIBC %s -o %t && %run %t
+// RUN: %clangxx -O1 -pthread %s -o %t && %run %t
+// RUN: %clangxx -O1 -pthread -DUSE_GLIBC %s -o %t && %run %t
 // UNSUPPORTED: android
 
 #include <pthread.h>