Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -275,6 +275,10 @@
   add_definitions(-DLIBCXXABI_HAS_NO_THREADS=1)
 endif()
 
+if (LIBCXXABI_HAS_PTHREAD_API)
+  add_definitions(-D_LIBCPP_HAS_THREAD_API_PTHREAD)
+endif()
+
 # This is the _ONLY_ place where add_definitions is called.
 if (MSVC)
   add_definitions(-D_CRT_SECURE_NO_WARNINGS)