Fix the memory leak related to Python 3 unicode and char * conversion.

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@11160 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -1,6 +1,21 @@
 Version 1.3.39 (in progress)
 ============================
 
+2009-03-19: bhy
+            [Python] Fix the memory leak related to Python 3 unicode and C char* conversion,
+            which can be shown in the following example before this fix:
+            
+                  from li_cstring import *
+                  i=0
+                  while True:
+                      i += 1
+                      n = str(i)*10
+                      test3(n)
+
+            This fix affected SWIG_AsCharPtrAndSize() so you cannot call this function with
+            a null alloc and non-null cptr argument in Python 3, otherwise a runtime error
+            will be raised.
+
 2009-03-18: wsfulton
 	    [C#] std::vector<T> wrapper improvements for .NET 2 and also providing the
 	    necessary machinery to use the std::vector<T> wrappers with more advanced features such