Include <sys/time.h> and <unistd.h> inside HAVE_x_H.

Added 'optind' and 'optarg' as in adig.c.

ares/ahost.c

@@ -19,13 +19,17 @@
 #include <sys/types.h>
 
 #if !defined(WIN32) || defined(WATT32)
+#ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
+#endif
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netdb.h>
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -40,6 +44,11 @@
 #include "inet_ntop.h"
 #include "inet_net_pton.h"
 
+#ifndef optind
+extern int   optind;
+extern char *optarg;
+#endif
+
 #ifndef INADDR_NONE
 #define INADDR_NONE 0xffffffff
 #endif