monitor: rename EVENT_* to QEVENT_* to avoid conflict on mingw32

Partially fixes mingw32 build.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/monitor.c b/monitor.c
index 5bf32f0..3cb3cf4 100644
--- a/monitor.c
+++ b/monitor.c
@@ -345,25 +345,25 @@
     const char *event_name;
     Monitor *mon = cur_mon;
 
-    assert(event < EVENT_MAX);
+    assert(event < QEVENT_MAX);
 
     if (!monitor_ctrl_mode(mon))
         return;
 
     switch (event) {
-        case EVENT_DEBUG:
+        case QEVENT_DEBUG:
             event_name = "DEBUG";
             break;
-        case EVENT_SHUTDOWN:
+        case QEVENT_SHUTDOWN:
             event_name = "SHUTDOWN";
             break;
-        case EVENT_RESET:
+        case QEVENT_RESET:
             event_name = "RESET";
             break;
-        case EVENT_POWERDOWN:
+        case QEVENT_POWERDOWN:
             event_name = "POWERDOWN";
             break;
-        case EVENT_STOP:
+        case QEVENT_STOP:
             event_name = "STOP";
             break;
         default: