that was of course my cursory effort which merely opened the way for more problems to appear. 

Sure, what are these problems?

It still insisted gcc wasn't working although the symbolic link as already suggested/done did get it to try gcc instead of a missing cc -- there were then more make test issues, missing directories and missing c header files perl needed e.g. sys/types.h.

Before switching to Ubuntu, so I can't reproduce it now, I concluded that gcc always needs a clean installation rather than a readymade delivery, i.e; either distros need to ship a slightly old gcc to make this upgrade possible or they need to schedule the compilation at the end of the first boot processing.

One world, one people