[CMake] Handle lib64 library on Linux

[Sara Rolfe]

Hello,

I am attempting to modify my make file so the linker will check for / 
usr/lib64 instead of /usr/lib.  I found a patch for this problem here:

http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=126c993d#patch1

However, I'm pretty new to cmake and it's not clear to me how to apply  
this.  Can someone explain, or point me to an example/documentation?

Thanks,
Sara