$ perl -E 'use XML::LibXML; say $XML::LibXML::VERSION'
2.0205

##</code><code>##

cpan[1]> install XML::LibXML
Reading '/home/ken/.cpan/Metadata'
  Database was generated on Fri, 01 Jan 2021 04:29:02 GMT
Running install for module 'XML::LibXML'
Fetching with LWP:
http://www.cpan.org/authors/id/S/SH/SHLOMIF/XML-LibXML-2.0206.tar.gz
Fetching with LWP:
http://www.cpan.org/authors/id/S/SH/SHLOMIF/CHECKSUMS
Checksum for /home/ken/.cpan/sources/authors/id/S/SH/SHLOMIF/XML-LibXML-2.0206.tar.gz ok
Scanning cache /home/ken/.cpan/build for sizes
............................................................................DONE
Configuring S/SH/SHLOMIF/XML-LibXML-2.0206.tar.gz with Makefile.PL
Checking if your kit is complete...
Looks good
Generating a Unix-style Makefile
Writing Makefile for XML::LibXML
Writing MYMETA.yml and MYMETA.json
  SHLOMIF/XML-LibXML-2.0206.tar.gz
  /home/ken/perl5/perlbrew/perls/perl-5.32.0/bin/perl Makefile.PL -- OK
Running make for S/SH/SHLOMIF/XML-LibXML-2.0206.tar.gz
cp lib/XML/LibXML/DocumentFragment.pod blib/lib/XML/LibXML/DocumentFragment.pod
... almost a screenful of successful 'cp' comands, then:
cp lib/XML/LibXML/Dtd.pod blib/lib/XML/LibXML/Dtd.pod
Running Mkbootstrap for LibXML ()
chmod 644 "LibXML.bs"
"/home/ken/perl5/perlbrew/perls/perl-5.32.0/bin/perl.exe" -MExtUtils::Command::MM -e 'cp_nonempty' -- LibXML.bs blib/arch/auto/XML/LibXML/LibXML.bs 644
gcc -c  -I/usr/include/libxml2 -DPERL_USE_SAFE_PUTENV -U__STRICT_ANSI__ -D_GNU_SOURCE -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -D_FORTIFY_SOURCE=2 -DUSEIMPORTLIB -O3   -DVERSION=\"2.0206\" -DXS_VERSION=\"2.0206\"  "-I/home/ken/perl5/perlbrew/perls/perl-5.32.0/lib/5.32.0/cygwin-thread-multi/CORE"  -DHAVE_UTF8 Av_CharPtrPtr.c
In file included from Av_CharPtrPtr.c:7:
/home/ken/perl5/perlbrew/perls/perl-5.32.0/lib/5.32.0/cygwin-thread-multi/CORE/perl.h:861:13: fatal error: xlocale.h: No such file or directory
  861 | #   include <xlocale.h>
      |             ^~~~~~~~~~~
compilation terminated.
make: *** [Makefile:438: Av_CharPtrPtr.o] Error 1
  SHLOMIF/XML-LibXML-2.0206.tar.gz
  /usr/bin/make -- NOT OK
Failed during this command:
 SHLOMIF/XML-LibXML-2.0206.tar.gz             : make NO

##</code><code>##

ken@titan /
$ find . -name 'xlocale.h' -print 2> /dev/null
./cygdrive/c/Users/ken/local/opt/strawberry_perl/5_026_003/install/perl/site/lib/Alien/wxWidgets/msw_3_0_2_uni_gcc_3_4/include/wx/xlocale.h
./cygdrive/c/Users/ken/local/opt/strawberry_perl/5_030_000/install/cpan/build/Alien-wxWidgets-0.69-0/blib/arch/Alien/wxWidgets/msw_3_0_2_uni_gcc_3_4/include/wx/xlocale.h
./cygdrive/c/Users/ken/local/opt/strawberry_perl/5_030_000/install/cpan/build/Alien-wxWidgets-0.69-0/wxWidgets-3.0.2/include/wx/xlocale.h
./cygdrive/c/Users/ken/local/opt/strawberry_perl/5_030_000/install/cpan/build/Alien-wxWidgets-0.69-0/wxWidgets-3.0.2/interface/wx/xlocale.h
./cygdrive/c/Users/ken/local/opt/strawberry_perl/5_030_000/install/perl/site/lib/Alien/wxWidgets/msw_3_0_2_uni_gcc_3_4/include/wx/xlocale.h
./usr/i686-pc-cygwin/sys-root/usr/include/xlocale.h
./usr/i686-w64-mingw32/sys-root/mingw/include/wx-3.0/wx/xlocale.h
./usr/include/c++/v1/support/fuchsia/xlocale.h
./usr/include/c++/v1/support/ibm/xlocale.h
./usr/include/c++/v1/support/musl/xlocale.h
./usr/include/c++/v1/support/newlib/xlocale.h
./usr/include/c++/v1/support/solaris/xlocale.h
./usr/include/c++/v1/support/xlocale/xlocale.h
./usr/include/wx-3.0/wx/xlocale.h
./usr/src/debug/wxWidgets3.0-3.0.4-1/include/wx/xlocale.h
./usr/x86_64-w64-mingw32/sys-root/mingw/include/wx-3.0/wx/xlocale.h