I do something similar in scripts that automate module
installation. However, I use a longer list of variables:
$makefile_args =
" INSTALLPRIVLIB=$prefix/usr/lib/perl5/5.6.0 " .
" INSTALLARCHLIB=$prefix/usr/lib/perl5/5.6.0/i386-linux " .
" INSTALLSITELIB=$prefix/usr/lib/perl5/site_perl/5.6.0 " .
" INSTALLSITEARCH=$prefix/usr/lib/perl5/site_perl/5.6.0/i386-linux " .
" INSTALLBIN=$prefix/usr/bin " .
" INSTALLSCRIPT=$prefix/usr/bin " .
" INSTALLMAN1DIR=$prefix/usr/share/man/man1 " .
" INSTALLMAN3DIR=$prefix/usr/share/man/man3 ";
All I do is set the $prefix. Voila! Modules where we
want 'em!