macro fix

macro fix

src/bio.h

@@ -27,6 +27,9 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#ifndef __BIO_H
+#define __BIO_H
+
 /* Exported API */
 void bioInit(void);
 void bioCreateBackgroundJob(int type, void *arg1, void *arg2, void *arg3);
@@ -40,3 +43,5 @@ void bioKillThreads(void);
 #define BIO_AOF_FSYNC     1 /* Deferred AOF fsync. */
 #define BIO_LAZY_FREE     2 /* Deferred objects freeing. */
 #define BIO_NUM_OPS       3
+
+#endif