Add unistd.h header for close function

git-svn-id: http://qboxcode.org/svn/qb/trunk@1407 cba15fb0-1239-40c8-b417-11db7ca47a34

src/XMLGFPreprocessor.C

@@ -24,6 +24,7 @@
 #include <cstdlib>
 #include <cstdio>
 #include <cassert>
+#include <unistd.h> // close
 
 #include <vector>
 #include <valarray>