I guess I haven't installed enough non-pure-Perl modules, but I can't figure this out. Here's what I'm seeing:

[root@localhost ~]# cpan make XML::LibXML
CPAN: Term::ANSIColor loaded ok (v4.02)
CPAN: Storable loaded ok (v2.34)
Reading '/root/.cpan/Metadata'
  Database was generated on Thu, 06 Mar 2014 11:17:02 GMT
Don't be silly, you can't install Matthias Kerk ;-)
CPAN: Time::HiRes loaded ok (v1.9725)
Running install for module 'XML::LibXML'
Running make for S/SH/SHLOMIF/XML-LibXML-2.0111.tar.gz
CPAN: Digest::SHA loaded ok (v5.84)
CPAN: Compress::Zlib loaded ok (v2.06)
Checksum for /root/.cpan/sources/authors/id/S/SH/SHLOMIF/XML-LibXML-2.
+0111.tar.gz ok
CPAN: Archive::Tar loaded ok (v1.90)
...
CPAN: File::Temp loaded ok (v0.22)
CPAN: Parse::CPAN::Meta loaded ok (v1.4404)
CPAN: CPAN::Meta loaded ok (v2.120921)
CPAN: Module::CoreList loaded ok (v2.80)

  CPAN.pm: Building S/SH/SHLOMIF/XML-LibXML-2.0111.tar.gz

enable native perl UTF8
running xml2-config...didn't manage to get libxml2 config, guessing
options:
  LIBS='-L/usr/local/lib -L/usr/lib -lxml2 -lm'
  INC='-I/usr/local/include -I/usr/include'
If this is wrong, Re-run as:
  $ /opt/ActivePerl-5.16/bin/perl-static Makefile.PL LIBS='-L/path/to/
+lib' INC='-I/path/to/include'

Checking for ability to link against xml2...no
Checking for ability to link against libxml2...libxml2, zlib, and/or t
+he Math library (-lm) have not been found.
Try setting LIBS and INC values on the command line
Or get libxml2 from
  http://xmlsoft.org/
If you install via RPMs, make sure you also install the -devel
RPMs, as this is where the headers (.h files) are.

Also, you may try to run perl Makefile.PL with the DEBUG=1 parameter
to see the exact reason why the detection of libxml2 installation
failed or why Makefile.PL was not able to compile a test program.
No 'Makefile' createdCPAN: YAML::XS loaded ok (v0.39)
  SHLOMIF/XML-LibXML-2.0111.tar.gz
  /opt/ActivePerl-5.16/bin/perl-static Makefile.PL INSTALLDIRS=site --
+ NOT OK
Running make test
  Make had some problems, won't test
Running make install
  Make had some problems, won't install
Could not read metadata file. Falling back to other methods to determi
+ne prerequisites
[download]

It looks like the LIBS is looking for xml2 not libxml2; only the latter is installed on my system.

[root@localhost ~]# find / -name 'xml2.so*'
[root@localhost ~]# find / -name 'libxml2.so*'
/usr/lib64/libxml2.so.2.6.26
/usr/lib64/libxml2.so.2
/usr/lib/libxml2.so.2.6.26
/usr/lib/libxml2.so.2
[root@localhost ~]#
[download]

Is there some way to override the value of LIBS from the cpan command line? Or do I need to figure out where to run the suggested 'perl-static Makefile.PL' command? Or is there something else I'm missing? Thanks!