The CONFIGURE_REQUIRES directive is only really required to be supported on the distribution author's 'machine', not
on end-users' machines.
App-EUMM-Upgrade is a good tool for upgrading a Makefile.PL that produces something like this, any fancy features will be removed when it is run on the end-users' configuration.
'configure_requires' itself is documented in the CPAN::Meta::Spec. CPAN clients ( such as cpan, cpanp and cpanm ) will read any META.yml/META.json file included with a distribution and resolve any modules listed as 'configure_requires' before executing Makefile.PL/Build.PL.