如何在OSX El Capitan上安装libxml-ruby gem 2.3.2？

Question

我正在尝试安装一个在Ruby 1.8.7-p370上运行的旧项目，并且该项目依赖于运行OS X El Capitan的Mac上的libxml-ruby 2.3.2 gem的旧版本。

问题是，当尝试安装gem时，它不会构建本机扩展。 这是运行gem install libxml-ruby -v '2.3.2'时的完整错误：

Building native extensions.  This could take a while...
ERROR:  Error installing libxml-ruby:
    ERROR: Failed to build gem native extension.

        /Users/myusername/.rbenv/versions/1.8.7-p370/bin/ruby extconf.rb
checking for socket() in -lsocket... no
checking for gethostbyname() in -lnsl... no
checking for atan() in -lm... no
checking for atan() in -lm... yes
checking for inflate() in -lz... yes
checking for iconv_open() in -liconv... yes
checking for xmlParseDoc() in -lxml2... yes
checking for libxml/xmlversion.h... yes
creating extconf.h
creating Makefile

make
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c libxml.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_attr.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_attr_decl.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_attributes.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_cbg.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_document.c
couldn't understand kern.osversion `15.6.0'
ruby_xml_document.c: In function ‘rxml_document_canonicalize’:
ruby_xml_document.c:334: warning: passing argument 4 of ‘xmlC14NDocDumpMemory’ from incompatible pointer type
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_dtd.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_encoding.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_error.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_html_parser.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_html_parser_context.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_html_parser_options.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_input_cbg.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_io.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_namespace.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_namespaces.c
couldn't understand kern.osversion `15.6.0'
/usr/local/bin/gcc-4.2 -I. -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include -DRUBY_EXTCONF_H=\"extconf.h\" -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE  -I/Users/myusername/.rbenv/versions/1.8.7-p370/include  -fno-common  -O3 -Wno-error=shorten-64-to-32  -pipe -fno-common  -I/usr/include/libxml2 -I. -I/Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/1.8/i686-darwin15.6.0 -I. -I/usr/local/include  -c ruby_xml_node.c
couldn't understand kern.osversion `15.6.0'
ruby_xml_node.c: In function ‘rxml_node_to_s’:
ruby_xml_node.c:622: error: dereferencing pointer to incomplete type
ruby_xml_node.c:624: error: dereferencing pointer to incomplete type
make: *** [ruby_xml_node.o] Error 1


Gem files will remain installed in /Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/gems/1.8/gems/libxml-ruby-2.3.2 for inspection.
Results logged to /Users/myusername/.rbenv/versions/1.8.7-p370/lib/ruby/gems/1.8/gems/libxml-ruby-2.3.2/ext/libxml/gem_make.out

我已经做了一些谷歌搜索，但是到目前为止，还没有找到解决该问题的方法。 这是我尝试过的一些方法。

一个建议是卸载apple-gcc可能有效，但这使我没有编译器来构建本机扩展。

另一篇文章建议 ，这与libxml-ruby 2.3.2和OS X随附的最新版本的libxml之间的不兼容有关。但是，以下内容不起作用，因为MacOSX10.8 SDK似乎未随Xcode一起提供不再。 还是我在那里缺少什么？

export SDKROOT=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk

我可以采取什么步骤来解决这个问题？ 谢谢你的帮助！

Answer 1

原来，问题确实是由不兼容的ruby gem版本和已安装的libxml版本引起的。 最后，我选择更新到较新的gem版本，以便正确构建。

如果您确实确实需要版本2.3.2，则显然也可以手动应用以下修补程序： https : //github.com/xml4r/libxml-ruby/commit/1c4878f3fdcd0cdf2e0fd09a5e6147a6ed237cf0