Después de actualizar a Snow Leopard, descubrí que la instalación de algunas gemas ya no funcionaba, incluido webrat, mecanizar, etc. Cada vez que recibo este error:

checking for xmlParseDoc() in -lxml2... no
libxml2 is missing.  try 'port install libxml2' or 'yum install libxml2'
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Y no, no he intentado instalarlo con macports, porque renuncié a macports hace un par de años cuando descubrí que no podía degradar / administrar fácilmente los puertos. Desde entonces, me he vuelto muy cómodo construyendo de origen a mano, y esta es la primera vez que me encuentro con algo que está más allá de mi conocimiento. Estoy dispuesto a ser persuadido para volver a Macport, pero solo si no hay una solución fácil, me estoy perdiendo.

No parece que falxml2 realmente esté faltando, ¿tal vez fuera de fecha? ...

salida extendida

ERROR: Failed to build gem native extension.

/usr/local/bin/ruby extconf.rb
checking for iconv.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for libxml/parser.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for libxslt/xslt.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for libexslt/exslt.h in /opt/local/include/,/opt/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for xmlParseDoc() in -lxml2... no
libxml2 is missing.  try 'port install libxml2' or 'yum install libxml2'
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/usr/local/bin/ruby
    --with-iconv-dir
    --without-iconv-dir
    --with-iconv-include
    --without-iconv-include=${iconv-dir}/include
    --with-iconv-lib
    --without-iconv-lib=${iconv-dir}/lib
    --with-xml2-dir
    --without-xml2-dir
    --with-xml2-include
    --without-xml2-include=${xml2-dir}/include
    --with-xml2-lib
    --without-xml2-lib=${xml2-dir}/lib
    --with-xslt-dir
    --without-xslt-dir
    --with-xslt-include
    --without-xslt-include=${xslt-dir}/include
    --with-xslt-lib
    --without-xslt-lib=${xslt-dir}/lib
    --with-xml2lib
    --without-xml2lib


Gem files will remain installed in /usr/local/lib/ruby/gems/1.8/gems/nokogiri-1.4.1 for inspection.
Results logged to /usr/local/lib/ruby/gems/1.8/gems/nokogiri-1.4.1/ext/nokogiri/gem_make.out