Include stdbool.h to allow C99 bool to be used

We have practically started requiring some C99 features, so might as
well finally go ahead and bring in the C99 bool as well.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

src/utils/includes.h

@@ -18,6 +18,7 @@
 
 #include <stdlib.h>
 #include <stddef.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <string.h>