When running libtool, report it as such

This looks like a copy&paste error from ancient times.

OTOH, both functions that identify themselves currently as "Linker" are called from

     let link = if staticLink
                   then SysTools.runLibtool
                   else SysTools.runLink

in DriverPipeline.hs. So they can be both regarded linkers. Please close if you think that we should stick to the latter interpretation.