From: Bernhard Walle <bernhard@bwalle.de>

 Subject: Fix compilation with gcc 4.9 (ptrdiff_t errors)

 This is a backport of following patch in ppl git

   commit 61d4e14dfd9f1121e9b4521dead5728b2424dd7c

   Author: Roberto Bagnara <bagnara@cs.unipr.it>

   Date:   Tue Apr 29 21:51:43 2014 +0200

       Added missing inclusions.  Use std::ptrdiff_t.

       (Thanks to Paulo Cesar Pereira de Andrade.)

 ---

  src/Congruence_System.defs.hh     |    3 ++-

  src/Constraint_System.defs.hh     |    3 ++-

  src/Generator_System.defs.hh      |    3 ++-

  src/Grid_Generator_System.defs.hh |    3 ++-

  4 files changed, 8 insertions(+), 4 deletions(-)

 --- a/src/Grid_Generator_System.defs.hh

 +++ b/src/Grid_Generator_System.defs.hh

 @@ -30,6 +30,7 @@ site: http://www.cs.unipr.it/ppl/ . */

  #include "Variables_Set.types.hh"

  #include "Grid.types.hh"

  #include <iosfwd>

 +#include <cstddef>

  namespace Parma_Polyhedra_Library {

 @@ -267,7 +268,7 @@ public:

    class const_iterator

      : public std::iterator<std::forward_iterator_tag,

  			   Grid_Generator,

 -			   ptrdiff_t,

 +			   std::ptrdiff_t,

  			   const Grid_Generator*,

  			   const Grid_Generator&>,

        private Generator_System::const_iterator {

 --- a/src/Congruence_System.defs.hh

 +++ b/src/Congruence_System.defs.hh

 @@ -33,6 +33,7 @@ site: http://www.cs.unipr.it/ppl/ . */

  #include "Grid.types.hh"

  #include "Grid_Certificate.types.hh"

  #include <iosfwd>

 +#include <cstddef>

  namespace Parma_Polyhedra_Library {

 @@ -235,7 +236,7 @@ public:

    class const_iterator

      : public std::iterator<std::forward_iterator_tag,

  			   Congruence,

 -			   ptrdiff_t,

 +			   std::ptrdiff_t,

  			   const Congruence*,

  			   const Congruence&> {

    public:

 --- a/src/Constraint_System.defs.hh

 +++ b/src/Constraint_System.defs.hh

 @@ -33,6 +33,7 @@ site: http://www.cs.unipr.it/ppl/ . */

  #include "Congruence_System.types.hh"

  #include <iterator>

  #include <iosfwd>

 +#include <cstddef>

  namespace Parma_Polyhedra_Library {

 @@ -204,7 +205,7 @@ public:

    class const_iterator

      : public std::iterator<std::forward_iterator_tag,

  			   Constraint,

 -			   ptrdiff_t,

 +			   std::ptrdiff_t,

  			   const Constraint*,

  			   const Constraint&> {

    public:

 --- a/src/Generator_System.defs.hh

 +++ b/src/Generator_System.defs.hh

 @@ -33,6 +33,7 @@ site: http://www.cs.unipr.it/ppl/ . */

  #include "Polyhedron.types.hh"

  #include "Poly_Con_Relation.defs.hh"

  #include <iosfwd>

 +#include <cstddef>

  namespace Parma_Polyhedra_Library {

 @@ -250,7 +251,7 @@ public:

    class const_iterator

      : public std::iterator<std::forward_iterator_tag,

  			   Generator,

 -			   ptrdiff_t,

 +			   std::ptrdiff_t,

  			   const Generator*,

  			   const Generator&> {

    public: