diff -rupN mesquite-2.1.2/include/Mesquite.hpp mesquite-2.1.2_mod/include/Mesquite.hpp
--- mesquite-2.1.2/include/Mesquite.hpp	2012-05-09 20:53:10.558214520 +0200
+++ mesquite-2.1.2_mod/include/Mesquite.hpp	2012-04-30 10:24:48.000000000 +0200
@@ -53,6 +53,7 @@
   #define MESQUITE_EXPORT
 #endif
 
+#include <cstddef>
 #include <cmath>
 #include <cfloat>
 #include <climits>