When trying to perl Makefile.pl XML-Parser-2.44 while chrooted in LFS, I get this error:

Checking if your kit is complete...
Looks good
Warning: prerequisite LWP::UserAgent 0 not found.
Have /tools/lib/perl5/5.26.0
Want /tools/lib/perl5/5.26.0/x86_64-linux
Your perl and your Config.pm seem to have different ideas about the
architecture they are running on.
Perl thinks: [5.26.0]
Config says: [x86_64-linux]
This may or may not cause problems. Please check your installation of perl
if you have problems building this extension.
Have /tools/lib/perl5/5.26.0
Want /tools/lib/perl5/5.26.0/x86_64-linux
Your perl and your Config.pm seem to have different ideas about the
architecture they are running on.
Perl thinks: [5.26.0]
Config says: [x86_64-linux]
This may or may not cause problems. Please check your installation of perl
if you have problems building this extension.
ERROR from evaluation of /sources/XML-Parser-2.44/Expat/Makefile.PL: Failed to opendir '/tools/lib/perl5/5.26.0/x86_64-linux/CORE' to find header files: No such file or directory at /tools/lib/perl5/5.26.0/ExtUtils/MM_Any.pm line 3027.

I have looked everywhere for an answer. Please help me.

It looks like you may not have compiled perl correctly as at this stage I do not think you should have references to /tools.

Usual story with LFS is that you need to follow the instructions exactly or you hit errors.

Consider posting the question to a venerable Perl-specialist web site, http://www.perlmonks.org. Many experts in that language lurk in that sometimes very-peculiar Monastery.