[SYCL] fix for windows compilation (#6408)

cperkinsintel · web-flow · commit 8262fd86e39e · 2022-07-06T11:10:29.000-07:00
#6388 overlooked inclusion needed for windows Signed-off-by: Chris Perkins <chris.perkins@intel.com>
diff --git a/sycl/source/detail/event_impl.hpp b/sycl/source/detail/event_impl.hpp
@@ -19,6 +19,7 @@
 #include <atomic>
 #include <cassert>
 #include <condition_variable>
+#include <optional>
 
 __SYCL_INLINE_NAMESPACE(cl) {
 namespace sycl {
