in reply to Module Makefile.PL conditional PREREQ_PM
No CPAN client uses what is listed in META.yml to resolve prereqs, they all run Makefile.PL to determine those.
CPAN clients will use the configure_requires field in META.yml to determine any prereqs that require resolving before Makefile.PL is executed.
Any other prereqs listed in META.yml may or may not be accurate, this is the price for a Turing complete build system
Both v1.4 of the META specification and CPAN::Meta::Spec deal with this using the 'dynamic_config' field.