+--- llvm-3.9.1.src/tools/lldb/include/lldb/Utility/TaskPool.h~ 2015-11-03 23:29:20.000000000 +0100
++++ llvm-3.9.1.src/tools/lldb/include/lldb/Utility/TaskPool.h 2018-02-19 15:48:34.116275467 +0100
+@@ -33,6 +33,7 @@
+ #include <queue>
+ #include <thread>
+ #include <vector>
++#include <functional>
+
+ // Global TaskPool class for running tasks in parallel on a set of worker thread created the first
+ // time the task pool is used. The TaskPool provide no gurantee about the order the task will be run