Fix Windows build

Fixes the issue introduced by c1a0ebb7 (Fix use of uninitialised variable
in class Event) causing Windows builds to fail

src/threading/event.cpp

@@ -26,7 +26,6 @@ DEALINGS IN THE SOFTWARE.
 #include "threading/event.h"
 
 Event::Event()
-    : notified(false)
 {
 #if __cplusplus < 201103L
 #	ifdef _WIN32
@@ -34,6 +33,7 @@ Event::Event()
 #	else
 	pthread_cond_init(&cv, NULL);
 	pthread_mutex_init(&mutex, NULL);
+	notified = false;
 #	endif
 #endif
 }