Fix define and conditional include for event_base_new in examples.

src/example/example-reverse.c

@@ -1,3 +1,9 @@
+#include "config.h"
+#ifdef HAVE_EVENT2_EVENT_H
+#  include <event2/event.h>
+#else
+#  include <event.h>
+#endif
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>

src/example/example-simple-answers.c

@@ -34,6 +34,12 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "config.h"
+#ifdef HAVE_EVENT2_EVENT_H
+#  include <event2/event.h>
+#else
+#  include <event.h>
+#endif
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>

src/example/example-tree.c

@@ -1,3 +1,9 @@
+#include "config.h"
+#ifdef HAVE_EVENT2_EVENT_H
+#  include <event2/event.h>
+#else
+#  include <event.h>
+#endif
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>