diff -Naur pdb2pqr-1.3.0/pdb2pka/pMC_mult.cpp pdb2pqr-1.3.0.new/pdb2pka/pMC_mult.cpp
--- pdb2pqr-1.3.0/pdb2pka/pMC_mult.cpp	2006-12-05 20:35:43.000000000 -0500
+++ pdb2pqr-1.3.0.new/pdb2pka/pMC_mult.cpp	2008-06-19 08:53:22.000000000 -0400
@@ -8,6 +8,8 @@
 //
 //
 
+#include <cstdlib>
+
 void MC::reformat_arrays() {
   //
   // Reformat the matrix