[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/include/common/compat.h b/include/common/compat.h
index 1bfe669..774f9b4 100644
--- a/include/common/compat.h
+++ b/include/common/compat.h
@@ -33,6 +33,7 @@
 
 /* This is needed on Linux for Netfilter includes */
 #include <sys/socket.h>
+#include <sys/types.h>
 #include <common/config.h>
 
 /* INTBITS
@@ -54,6 +55,13 @@
 #define SHUT_WR	        1
 #endif
 
+/* AIX does not define MSG_DONTWAIT. We'll define it to zero, and test it
+ * wherever appropriate.
+ */
+#ifndef MSG_DONTWAIT
+#define MSG_DONTWAIT	0
+#endif
+
 #if defined(TPROXY) && defined(NETFILTER)
 #include <linux/netfilter_ipv4.h>
 #endif
diff --git a/include/common/time.h b/include/common/time.h
index ced4b6b..2a4a142 100644
--- a/include/common/time.h
+++ b/include/common/time.h
@@ -485,7 +485,7 @@
         tv1;                       \
 })
 
-char *human_time(int t, short hz);
+char *human_time(int t, short hz_div);
 
 #endif /* _COMMON_TIME_H */
 
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 */
 	}
     
diff --git a/src/proxy.c b/src/proxy.c
index 640a2c1..06424c6 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -12,6 +12,7 @@
 
 #include <fcntl.h>
 #include <unistd.h>
+#include <string.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
diff --git a/src/time.c b/src/time.c
index bb98d98..661c7e2 100644
--- a/src/time.c
+++ b/src/time.c
@@ -142,18 +142,18 @@
 	return __tv_isgt(tv1, tv2);
 }
 
-char *human_time(int t, short hz) {
+char *human_time(int t, short hz_div) {
 	static char rv[sizeof("24855d23h")+1];	// longest of "23h59m" and "59m59s"
 	char *p = rv;
 	int cnt=2;				// print two numbers
 
-	if (unlikely(t < 0 || hz <= 0)) {
+	if (unlikely(t < 0 || hz_div <= 0)) {
 		sprintf(p, "?");
 		return rv;
 	}
 
-	if (unlikely(hz > 1))
-		t /= hz;
+	if (unlikely(hz_div > 1))
+		t /= hz_div;
 
 	if (t >= DAY) {
 		p += sprintf(p, "%dd", t / DAY);