Building using command line tools

Hi,

        I am building the application on s60 3rd edition using command line 
tools such as makmake and abld.

        I found either we can do it either way. Which is the recommended way 
to do builds ? In case of makmake, is it possible  to
        makefile which doesnot have relative paths.

        Also I am integrating the symbian build env with our in-house one 
which uses nmake instead of GNU make.

        The Perl versions are different in both and the modules are in 
different paths. How to co-exist both ? any ideas

Thx,
Anand