Don't try to guess by the things in $ENV{PATH} - use Config. $Config{cc} has whatever C compiler should be used, $Config{make} has whatever make program should be used.

As you don't show any code, I can only give you vague and general hints. You will have to output different postambles depending on the type of make program (nmake, make, dmake), as they all use a different syntax. You will also have to set the CFLAGS variable depending on whether you need -shared or /link.