- Remove duplicate macro defintions.


CMakeLists.txt:
  Bug #23839 Multiple declarations of macros
  - Make sure _WIN64 is defined for proper Intellisense functionality.
include/config-win.h:
  Bug #23839 Multiple declarations of macros
  - Remove extra definitions.  Use the my_global.h defines instead.
include/my_global.h:
  Bug #23839 Multiple declarations of macros
  - Slight change to maintain current definitions for Windows.