Add support for Solaris 2.6 on sun4m builds

It is an excellent platform for catching bugs: big-endian, slow enough
that a context switch in the middle of an operation becomes a regular
occurrence, and all that on a SMP box.  Or: I just wanted to see if it
would work.

Signed-off-by: Erik Boasson <eb@ilities.com>

src/tools/ddsperf/ddsperf.c

@@ -10,6 +10,7 @@
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  */
 #define _ISOC99_SOURCE
+#define _POSIX_PTHREAD_SEMANTICS
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -19,7 +20,9 @@
 #include <assert.h>
 #include <limits.h>
 #include <math.h>
+#if _WIN32
 #include <getopt.h>
+#endif
 
 #include "dds/dds.h"
 #include "ddsperf_types.h"