CMake updates:

CMake updates:
- no longer trying to link with m.lib (tht maths for linux)
- now building demos for static and for shared library, depending on
  which libraries are created
- TARGET_LINK_LIBRARIES statement conditional on whether the relevant
  shared/static library is built

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@1098 7f0cb862-5218-0410-a997-914c9d46530a