--- MUSTANG_v3.2.1.orig/src/superpose_on_core_2.cpp	2009-04-18 10:30:17.000000000 +0200
+++ MUSTANG_v3.2.1/src/superpose_on_core_2.cpp	2014-04-02 23:44:58.668808458 +0200
@@ -54,6 +54,7 @@
 #include "read_structures.h"
 #include "multiple_superposition.h"
 #include "3D_manip_functions.h"
+#include "unistd.h"
 
 int **core_columns ;
 int *core_columns_2 , NCORE = 0 ;
