Allow the use of Visual Leak Detector

See the small feature [[Small features/Visual_Leak_Detector]] in CGAL
developers wiki:
  https://cgal.geometryfactory.com/CGAL/Members/wiki/Features/Small_Features/Visual_Leak_Detector

See also:
  http://vld.codeplex.com/

Installation/cmake/modules/CGAL_Common.cmake

@@ -50,6 +50,15 @@ if( NOT CGAL_COMMON_FILE_INCLUDED )
       endif()
     endif()
     hide_variable(CMAKE_UNAME)
+
+    # Optionally setup the Visual Leak Detector
+    include(CGAL_SetupVLD)
+    CGAL_SetupVLD()
+    if(VLD_FOUND)
+      message(STATUS "Visual Leak Detector (VLD) is enabled.")
+    else()
+      message(STATUS "Visual Leak Detector (VLD) is not found.")
+    endif()
   endif()
 
   set(CMAKE_COLORMAKEFILE ON)

Installation/cmake/modules/CGAL_SetupVLD.cmake

@@ -0,0 +1,37 @@
+function(CGAL_setupVLD)
+
+  if(DEFINED ENV{CGAL_ENABLE_VLD} AND NOT DEFINED CGAL_ENABLE_VLD)
+    set(CGAL_ENABLE_VLD $ENV{CGAL_ENABLE_VLD})
+  endif()
+
+  if(CGAL_ENABLE_VLD)
+    find_path(VLD_INCLUDE_DIR vld.h
+      HINTS $ENV{VLD_INCLUDE_DIR}
+            $ENV{VLD_HOME}/include
+            $ENV{VLD_HOME}
+      DOC "Path of the Visual Leak Detector header vld.h"
+    )
+
+    find_library(VLD_LIBRARY
+      NAMES vld-x86 vld
+      HINTS ${VLD_LIBRARY_DIR}
+            $ENV{VLD_LIBRARY_DIR}
+            $ENV{VLD_HOME}/lib
+            $ENV{VLD_HOME}
+            ${VLD_INCLUDE_DIR}
+            ${VLD_INCLUDE_DIR}/lib
+      DOC "Path of the Visual Leak Detector library vld.lib"
+    )
+    if(VLD_LIBRARY)
+      get_filename_component(VLD_LIBRARY_DIR "${VLD_LIBRARY}" PATH CACHE)
+    endif()
+
+    if(VLD_INCLUDE_DIR AND VLD_LIBRARY_DIR)
+      set(VLD_FOUND 1 PARENT_SCOPE)
+      include_directories(${VLD_INCLUDE_DIR})
+      link_directories(${VLD_LIBRARY_DIR})
+      add_definitions(-DCGAL_ENABLE_VLD)
+    endif()
+
+  endif(CGAL_ENABLE_VLD)
+endfunction()

Installation/include/CGAL/config.h

@@ -1,4 +1,4 @@
-// Copyright (c) 1997-2010  
+// Copyright (c) 1997-2013
 // Utrecht University (The Netherlands),
 // ETH Zurich (Switzerland),
 // INRIA Sophia-Antipolis (France),
@@ -23,6 +23,7 @@
 // Author(s)     : Wieger Wesselink 
 //                 Michael Hoffmann <hoffmann@inf.ethz.ch>
 //                 Sylvain Pion
+//                 Laurent Rineau
 
 #ifndef CGAL_CONFIG_H
 #define CGAL_CONFIG_H
@@ -43,6 +44,12 @@
 #  error The test-suite needs no NDEBUG defined
 #endif // CGAL_TEST_SUITE and NDEBUG
 
+// See [[Small features/Visual_Leak_Detector]] in CGAL developers wiki
+// See also: http://vld.codeplex.com/
+#if defined(CGAL_ENABLE_VLD)
+#  include <vld.h>
+#endif // CGAL_ENABLE_VLD
+
 // Workaround to the following bug:
 //   https://bugreports.qt.nokia.com/browse/QTBUG-22829
 #ifdef Q_MOC_RUN