Added FREEGLUT_REPLACE_GLUT configure option for MS Windows.

It provides back compatibility with older (autotools based) freeglut versions.
Also it simplifies build rules for crossplatform programs: they may be linked
with -lglut regardless of the system and library type (shared/static).

Patch is originally prepared for MXE project (http://mxe.cc/).

(cherry picked from commit cd9ac605ec4615569121e0e9b6bc058684bebfe3)

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@1793 7f0cb862-5218-0410-a997-914c9d46530a