[CMake] Passing -B on linux

[Bill Hoffman]

Juan Sanchez wrote:
> Hello gga,
>
> Unfortunately, the ADD_DEFINITIONS aren't being used in the initial
> tests being done by cmake.  What I've found is that I need to put the
> location of the 64bit linker utils needed by g++ in my PATH.  In this
> instance, its calling the wrong assembler.  The assembler is implicitly
> called by g++ and -B would allow me to set the path.
>   
If you set environment variables BEFORE running cmake, it should use 
them in the try compile
stuff:

Something like this:

export CXX=g++
export CXXFLAGS=-64
export LDFLAGS=-64
export CFLAGS=-64