fix #include of project header

Signed-off-by: Daniel A. Steffen <dsteffen@apple.com>

Author: das

src/shims.h

@@ -42,7 +42,7 @@
 #if __has_include(<pthread/workqueue_private.h>)
 #include <pthread/workqueue_private.h>
 #elif DISPATCH_USE_INTERNAL_WORKQUEUE
-#include <event/workqueue_internal.h>
+#include "event/workqueue_internal.h"
 #else
 #include <pthread_workqueue.h>
 #endif