pcap: Use clock_gettime() instead of gettimeofday()

POSIX.1-2008 declared gettimeofday() as obsolete, but I'm a dinosaur.

Usually, C libraries translate that to the clock_gettime() system
call anyway, but this doesn't happen in Jon's environment, and,
there, seccomp happily kills pasta(1) when started with --pcap,
because we didn't add gettimeofday() to our seccomp profiles.

Use clock_gettime() instead.

Reported-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

util.h

@@ -40,6 +40,7 @@
 #endif
 
 #define DIV_ROUND_UP(n, d)	(((n) + (d) - 1) / (d))
+#define DIV_ROUND_CLOSEST(n, d)	(((n) + (d) / 2) / (d))
 #define ROUND_DOWN(x, y)	((x) & ~((y) - 1))
 #define ROUND_UP(x, y)		(((x) + (y) - 1) & ~((y) - 1))