error-report.h: Supply missing include

Missed in commit e5924d89.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NLaszlo "ever the optimist" Ersek <lersek@redhat.com>
Message-id: 1370610036-10577-2-git-send-email-armbru@redhat.com
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

include/qemu/error-report.h

@@ -14,6 +14,7 @@
 #define QEMU_ERROR_H
 
 #include <stdarg.h>
+#include "qemu/compiler.h"
 
 typedef struct Location {
     /* all members are private to qemu-error.c */