diff --git a/CMake/CTestCustom.cmake.in b/CMake/CTestCustom.cmake.in
index 4932050c67c591f62232be3d52873fc5578b28cc..eee64e2629ccbdf125748e3e47a4ca7810f181ac 100644
--- a/CMake/CTestCustom.cmake.in
+++ b/CMake/CTestCustom.cmake.in
@@ -1,11 +1,11 @@
 #
-# Note that the ITK/CMakeLists.txt file configures this file
+# Note that the OTB/CMakeLists.txt file configures this file
 #
 #               CMake/CTestCustom.cmake.in
 #
 # to this file
 #
-#       ${ITK_BINARY_DIR}/CTestCustom.cmake
+#       ${OTB_BINARY_DIR}/CTestCustom.cmake
 #
 #----------------------------------------------------------------------
 #
@@ -53,7 +53,6 @@ SET(CTEST_CUSTOM_WARNING_EXCEPTION
   "Fl_Image.H:.*warning:.*dereferencing type-punned pointer will break strict-aliasing rules.*"
   "warning -.: directory name .* does not exist"
   "ld.*warning.*duplicate dylib.*"
-  ".*pyconfig.h:.*warning:.*XOPEN.*SOURCE.*redefined.*"
   "WARNING non-zero return value in ctest"
   ".*Microsoft.*include.*.h.*[Ww]arning.*"
   ".*gdal_priv.h.*[Ww]arning.*"
diff --git a/Code/Wrappers/SWIG/itkPyCommand.h b/Code/Wrappers/SWIG/itkPyCommand.h
index cc157899a6b858898d21013a8c4d877cef44a0b4..ec0ef722686119bcd94c42c289875b50abe53614 100644
--- a/Code/Wrappers/SWIG/itkPyCommand.h
+++ b/Code/Wrappers/SWIG/itkPyCommand.h
@@ -21,6 +21,9 @@
 
 // The python header defines _POSIX_C_SOURCE without a preceding #undef
 #undef _POSIX_C_SOURCE
+// The python header defines _XOPEN_SOURCE without a preceding #undef
+#undef _XOPEN_SOURCE
+
 #include <Python.h>
 
 namespace itk