Add missing stdlib.h include and fix solaris_audit_failure() error return.

plugins/sudoers/solaris_audit.c

@@ -27,6 +27,7 @@
 
 #include <stdarg.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <limits.h>
 #include <unistd.h>
@@ -130,7 +131,7 @@ solaris_audit_failure(int argc, char *argv[], char const *const fmt, va_list ap)
 	adt_free_event(event);
 	(void) adt_end_session(ah);
 
-	return 0;
+	return rc;
 }
 
 #endif /* HAVE_SOLARIS_AUDIT */