Alien::Base::Wrapper->mm_args2() overwrites existing prereq versions

[johannessen]

When setting CONFIGURE_REQUIRES, “mm_args2” in Alien::Base::Wrapper disregards a required minimum version that’s already present in the arguments:

my %mm_args2 = Alien::Base::Wrapper->mm_args2(
  CONFIGURE_REQUIRES => {
    'ExtUtils::MakeMaker' => '7.12',  # first EU:MM version with the XSMULTI feature
  },
  XSMULTI => 1,
);

say $mm_args2{CONFIGURE_REQUIRES}{'ExtUtils::MakeMaker'};

# Expected:  7.12
# Actual:    6.52