From 8ca6e8dc15502867e5d32e279644f1758724a2f2 Mon Sep 17 00:00:00 2001
From: Jean-Christophe Fillion-Robin <jchris.fillionr@kitware.com>
Date: Wed, 22 Jun 2022 20:15:43 -0400
Subject: [PATCH] COMP: Fix older gcc build error including "cstddef" for
 "ptrdiff_t"
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This commit fixes a regression likely introduced in c173dfd80 (STYLE: Remove
`std::` prefix from types that work without it) to support building ITK
wheels using manylinux_2_24 providing gcc 6.3.

It fixes build error like the following:

  In file included from /work/ITK-source/ITK/Modules/Core/Common/include/itkImageRegion.h:33:0,
                   from /work/ITK-source/ITK/Modules/Core/Common/include/itkMultiThreaderBase.h:35,
                   from /work/ITK-source/ITK/Modules/Core/Common/src/itkTotalProgressReporter.cxx:19:
  /work/ITK-source/ITK/Modules/Core/Common/include/itkSize.h:242:27: error: ‘ptrdiff_t’ does not name a type
     using difference_type = ptrdiff_t;
                             ^~~~~~~~~
---
 Modules/Compatibility/Deprecated/include/itkAtomicInt.h | 1 +
 Modules/Core/Common/include/itkIndex.h                  | 2 ++
 Modules/Core/Common/include/itkOffset.h                 | 2 ++
 Modules/Core/Common/include/itkSize.h                   | 1 +
 Modules/IO/ImageBase/include/itkImageSeriesReader.hxx   | 1 +
 5 files changed, 7 insertions(+)

diff --git a/Modules/Compatibility/Deprecated/include/itkAtomicInt.h b/Modules/Compatibility/Deprecated/include/itkAtomicInt.h
index d587551715d3..bc1770d4decf 100644
--- a/Modules/Compatibility/Deprecated/include/itkAtomicInt.h
+++ b/Modules/Compatibility/Deprecated/include/itkAtomicInt.h
@@ -39,6 +39,7 @@
 #include "itkConceptChecking.h"
 
 #include <atomic>
+#include <cstddef>     // For ptrdiff_t.
 
 
 namespace itk
diff --git a/Modules/Core/Common/include/itkIndex.h b/Modules/Core/Common/include/itkIndex.h
index 0daa838d3c07..b5c1c75f9cac 100644
--- a/Modules/Core/Common/include/itkIndex.h
+++ b/Modules/Core/Common/include/itkIndex.h
@@ -20,6 +20,8 @@
 
 #include "itkMakeFilled.h"
 #include "itkOffset.h"
+
+#include <cstddef>     // For ptrdiff_t.
 #include <type_traits> // For is_integral.
 
 namespace itk
diff --git a/Modules/Core/Common/include/itkOffset.h b/Modules/Core/Common/include/itkOffset.h
index e0e55f8c2dd6..b2da9349743f 100644
--- a/Modules/Core/Common/include/itkOffset.h
+++ b/Modules/Core/Common/include/itkOffset.h
@@ -21,6 +21,8 @@
 #include "itkSize.h"
 #include "itkMath.h"
 
+#include <cstddef>     // For ptrdiff_t.
+
 namespace itk
 {
 
diff --git a/Modules/Core/Common/include/itkSize.h b/Modules/Core/Common/include/itkSize.h
index 55bdc508b48f..3dda87717db4 100644
--- a/Modules/Core/Common/include/itkSize.h
+++ b/Modules/Core/Common/include/itkSize.h
@@ -22,6 +22,7 @@
 #include "itkMacro.h"
 #include "itkMakeFilled.h"
 #include <algorithm>   // For copy_n.
+#include <cstddef>     // For ptrdiff_t.
 #include <type_traits> // For is_integral.
 #include <memory>
 
diff --git a/Modules/IO/ImageBase/include/itkImageSeriesReader.hxx b/Modules/IO/ImageBase/include/itkImageSeriesReader.hxx
index c1b78f24c8d5..bea2d4d2b926 100644
--- a/Modules/IO/ImageBase/include/itkImageSeriesReader.hxx
+++ b/Modules/IO/ImageBase/include/itkImageSeriesReader.hxx
@@ -25,6 +25,7 @@
 #include "itkMath.h"
 #include "itkProgressReporter.h"
 #include "itkMetaDataObject.h"
+#include <cstddef>     // For ptrdiff_t.
 #include <iomanip>
 
 namespace itk