MSVC_VERSION
------------

The version of Microsoft Visual C/C++ being used if any.

Known version numbers are::

  1200 = VS  6.0
  1300 = VS  7.0
  1310 = VS  7.1
  1400 = VS  8.0
  1500 = VS  9.0
  1600 = VS 10.0
  1700 = VS 11.0
  1800 = VS 12.0
  1900 = VS 14.0