perl is built with . in INC by default

[stigtsp]

default_inc_excludes_dot defaults to undef when building cross building perl, not sure if this is intentional.

-Ddefault_inc_excludes_dot is needed to avoid this in NixOS/nixpkgs#98466

[arsv]

Updated to match current mainline perl.

For some reason, it was "define" for cperl but "undef" for regular perl.
Most likely matching respective defaults at the time it was added.

perl-cross/cnf/configure_version.sh

Lines 60 to 68 in c2707f4

	# These should have been in _misc but the setting differ between
	# mainline perl and cperl.
	if [ "$package" = "cperl" ]; then
	define fake_signatures 'define'
	define default_inc_excludes_dot 'define'
	else
	define default_inc_excludes_dot 'undef'
	fi

[stigtsp]

@arsv thx for quick fix! 👍