CMake now prohibits configuring thread-safety w/ Fortran and C++.

These changes only apply to non-Cygwin Windows since CMake does not allow configuring thread-safety on any other platform.

Tested on 64-bit Windows 7.

git-svn-id: https://svn.hdfgroup.uiuc.edu/hdf5/trunk@24893 dab4d1a6-ed17-0410-a064-d1ae371a2980