[BUILD] fix 2 minor issues on AIX

AIX does not know about MSG_DONTWAIT. Fortunately, nearly all sockets
are already set to O_NONBLOCK, so it's not even required to change the
code.  It was only necessary to add this fcntl to the log socket which
lacked it.  The MSG_DONTWAIT value has been defined to zero when unset
in order to make the code cleaner and more portable.

Also, on AIX, "hz" is defined, which causes a problem with one function
parameter in time.c. It's enough to rename the parameter there. Last,
fix a missing #include <string.h> in proxy.c.
diff --git a/src/log.c b/src/log.c
index 5566d1a..20f9bb4 100644
--- a/src/log.c
+++ b/src/log.c
@@ -10,6 +10,7 @@
  *
  */
 
+#include <fcntl.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -165,6 +166,9 @@
 			return;
 		/* we don't want to receive anything on this socket */
 		setsockopt(logfd, SOL_SOCKET, SO_RCVBUF, &zero, sizeof(zero));
+		/* need for AIX which does not know about MSG_DONTWAIT */
+		if (!MSG_DONTWAIT)
+			fcntl(logfd, F_SETFL, O_NONBLOCK);
 		shutdown(logfd, SHUT_RD); /* does nothing under Linux, maybe needed for others */
 	}