I am the maintainer of the Perl module Net::Z3950::SimpleServer. When I run my Makefile.PL on my MacBook Pro Mid-2015, running MacOS Monterey 12.7.5, I get ten "mostly harmless" warnings about libraries that the build process can't find: 
$ perl Makefile.PL 
Checking if your kit is complete...
Looks good
Warning (mostly harmless): No library found for -lexslt
Warning (mostly harmless): No library found for -lxslt
Warning (mostly harmless): No library found for -lxml2
Warning (mostly harmless): No library found for -lz
Warning (mostly harmless): No library found for -lpthread
Warning (mostly harmless): No library found for -licucore
Warning (mostly harmless): No library found for -lm
Warning (mostly harmless): No library found for -lxml2
Warning (mostly harmless): No library found for -liconv
Warning (mostly harmless): No library found for -lpthread
Generating a Unix-style Makefile
Writing Makefile for Net::Z3950::SimpleServer
Writing MYMETA.yml and MYMETA.json

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Something more significant is going wrong with dynamic libraries later on when I run "make test", and I would like to narrow down the scope of my bewilderment by ruling out these early complains. Can anyone explain exactly what these "mostly harmless" warnings are telling me, and what if anything I can do to avoid them? Thank you!

In reply to Warning (mostly harmless): No library found for -lxml2 by MikeTaylor

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