I don't understand your explanation. But it could certainly cause a problem for me. I currently have Strawberry Perl first in $PATH and when I want to build a module for non-strawberry Perl, I run "bperl Makefile.PL; nmake ...". That would fail if Strawberry Perl had installed a non-nmake program as "nmake".

And the proposed solution sounds like the wrong way to go anyway. If Tk is using the wrong "make", then Tk should be patched to ask Perl which make to use. Making "nmake" mean "either nmake or some other make, depending on which order things are in $PATH" just makes things more confusing.