sim: v850: cleanup build warnings

This port only had one minor warning left in it, so fix it and then
enable -Werror behavior by deleting the macro call.  We'll use the
common default now (which is -Werror).

sim/v850/simops.c

@@ -11,6 +11,7 @@
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
+#include <stdlib.h>
 #include <string.h>
 
 #include "targ-vals.h"