-export MAKEFLAGS+=' POD2MAN=/usr/lib/perl5/core_perl/bin/pod2man'
-export MAKEFLAGS+=' POD2HTML=/usr/lib/perl5/core_perl/bin/pod2html'
-export MAKEFLAGS+=' PROVE=/usr/lib/perl5/core_perl/bin/prove'
+core_perl_dir='/usr/bin/core_perl'
+export MAKEFLAGS+=" POD2MAN=${core_perl_dir}/pod2man"
+export MAKEFLAGS+=" POD2HTML=${core_perl_dir}/pod2html"
+export MAKEFLAGS+=" PROVE=${core_perl_dir}/prove"