Fix compilation on NetBSD, which require sys/stat.h header file.

src/FqBaseBackend.cpp

@@ -4,6 +4,9 @@
  *  Created on: Jan 20, 2016
  *      Author: vlegrand
  */
+
+#include <sys/stat.h>
+
 #include <string>
 #include <stdexcept>
 #include <fcntl.h>

src/FqMainBackend.cpp

@@ -5,6 +5,8 @@
  *      Author: vlegrand
  */
 
+#include <sys/stat.h>
+
 #include <stdio.h>
 //#include <stdlib.h>
 #include <fcntl.h>

src/unit_test_fqwriter.cpp

@@ -4,6 +4,9 @@
  *  Created on: Mar 14, 2016
  *      Author: vlegrand
  */
+
+#include <sys/stat.h>
+
 #include <cstdio>
 #include <cassert>
 #include <unistd.h>