Thanks - that does look like a better way of doing what I have done. Of course both solutions still seem a little clumsy because they have to be done on a system wide basis using administrator privilege.

Makes me wonder if it wouldn't perhaps be better to implement such alternatives in a more flexible way, that is better suited to a multi-user system. for example, having /usr/bin/gccx.y directories, with compiler components having their standard names in each. The symlinks would then be, for example, gcc-ar -> gcc4.8/gcc-ar etc.

The advantage would be that any user could locally force one or other option by putting /usr/bin/gccx.y in their path before /usr/bin.