Add mysnprintf.c to Windows build, + squash compiler wngs in mysnprintf.c.

PCbuild/pythoncore.dsp

@@ -1163,6 +1163,21 @@ SOURCE=..\Parser\myreadline.c
 # End Source File
 # Begin Source File
 
+SOURCE=..\Python\mysnprintf.c
+
+!IF  "$(CFG)" == "pythoncore - Win32 Release"
+
+!ELSEIF  "$(CFG)" == "pythoncore - Win32 Debug"
+
+!ELSEIF  "$(CFG)" == "pythoncore - Win32 Alpha Debug"
+
+!ELSEIF  "$(CFG)" == "pythoncore - Win32 Alpha Release"
+
+!ENDIF 
+
+# End Source File
+# Begin Source File
+
 SOURCE=..\Python\mystrtoul.c
 
 !IF  "$(CFG)" == "pythoncore - Win32 Release"

Python/mysnprintf.c

@@ -37,9 +37,10 @@ int myvsnprintf(char *str, size_t size, const char  *format, va_list va)
 	return len;
     }
     len++;
-    if (len > size + 512)
+    assert(len >= 0);
+    if ((size_t)len > size + 512)
 	Py_FatalError("Buffer overflow in PyOS_snprintf/PyOS_vsnprintf");
-    if (len > size) {
+    if ((size_t)len > size) {
 	PyMem_Free(buffer);
 	return len - 1;
     }