Added missing include.

src/main.cc

@@ -31,6 +31,8 @@
 #include <stdlib.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <pthread.h>
+#include <semaphore.h>
 #include <unistd.h>
 #include <syslog.h>
 #include <string.h>