TSAN exclusion for libc++

test/thread_safety/Jamfile

@@ -24,6 +24,12 @@ local tests =
 
 for test in $(tests)
 {
+    # TSAN seems to raise a false positive with libc++ shared_ptr/weak_ptr, used in this test
+    local libcpp_exclusion ;
+    if $(test) = "connection_pool_cancel_get_connection" {
+        libcpp_exclusion = <stdlib>libc++:<build>no ;
+    }
+
     # In OSX, tsan reports a race condition in Asio's kqueue reactor. Ignore this for now.
     # Net TS executors use std::atomic_thread_fence, unsupported by TSAN, which yields false positives.
     # gcc-5 seems to emit incorrect tsan instrumentation code for static initializations
@@ -36,6 +42,7 @@ for test in $(tests)
             <target-os>darwin:<build>no
             <boost.mysql.use-ts-executor>on:<build>no
             <toolset>gcc-5:<build>no
+            $(libcpp_exclusion)
             <thread-sanitizer>norecover
         : target-name $(test)
     ;