Now find_newer_gplusplus can find g++ 4.8
Now find_newer_gplusplus can find g++ 4.8

Just added `8` to the array inside the function. Is there a more robust way to
do this? If I didn't know about extconf.rb and how it's structured, I wouldn't
have done this change. There's going to be g++ 4.9, 5.0, etc eventually. :(

thisMagpie/nmatrix,agisga/nmatrix,johnmarinelli/nmatrix,wlevine/nmatrix,wlevine/nmatrix,agisga/nmatrix,janusnic/nmatrix,janusnic/nmatrix,janusnic/nmatrix,agisga/nmatrix,wlevine/nmatrix,agisga/nmatrix,johnmarinelli/nmatrix,wlevine/nmatrix,thisMagpie/nmatrix,thisMagpie/nmatrix,janusnic/nmatrix,johnmarinelli/nmatrix,thisMagpie/nmatrix,johnmarinelli/nmatrix