trace: count number of enabled events

This lets trace_event_get_state_dynamic quickly return false.  Right
now there is hardly any benefit because there are also many assertions
and indirections, but the next patch will streamline all of this.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/trace/control.c b/trace/control.c
index 995beb384c..95fbc07c3c 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -16,6 +16,8 @@
 #endif
 #include "qemu/error-report.h"
 
+int trace_events_enabled_count;
+
 TraceEvent *trace_event_name(const char *name)
 {
     assert(name != NULL);