OSX libxml2 error fix

Ohhh noes.txt

Look like brew libxml2 and the one bundled with osx are fighting

/Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/libxml-ruby-1.1.4/lib/libxml_ruby.bundle: dlsym(0x7ffb44ee7880, Init_libxml_ruby): symbol not found - /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/libxml-ruby-1.1.4/lib/libxml_ruby.bundle (LoadError)
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/libxml-ruby-1.1.4/lib/libxml.rb:9
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/bundler-1.0.15/lib/bundler/runtime.rb:68:in `require'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/bundler-1.0.15/lib/bundler/runtime.rb:68:in `require'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/bundler-1.0.15/lib/bundler/runtime.rb:66:in `each'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/bundler-1.0.15/lib/bundler/runtime.rb:66:in `require'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/bundler-1.0.15/lib/bundler/runtime.rb:55:in `each'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/bundler-1.0.15/lib/bundler/runtime.rb:55:in `require'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/bundler-1.0.15/lib/bundler.rb:120:in `require'
	from /Users/unixcharles/projects/teambox/config/application.rb:7
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/railties-3.1.0/lib/rails/commands.rb:52:in `require'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/railties-3.1.0/lib/rails/commands.rb:52
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/railties-3.1.0/lib/rails/commands.rb:49:in `tap'
	from /Users/unixcharles/.rvm/gems/ruby-1.8.7-p352/gems/railties-3.1.0/lib/rails/commands.rb:49
	from script/rails:6:in `require'
	from script/rails:6

This fixed it for me:

brew update
brew uninstall libxml2
brew install libxml2 --with-xml2-config
brew link libxml2
gem uninstall libxml-ruby
bundle

(y)

Worked great! Thanks @khash!

If you don't want to link libxml2:

brew install libxml2 --with-xml2-config
gem install libxml-ruby -- --with-xml2-config=/usr/local/opt/libxml2/bin/xml2-config
bundle

@tamalw I owe you so many beers!

Since this was a top result while googling, I'll share my experience resolving this and the solution I found.

System: OSX 10.14
Homebrew: 2.7.2

The flag --with-xml2-config doesn't seem to work anymore with brew (I got a usage error with the command above). This comment from a Twilio issue was helpful in that it explained brew isn't needed and how to figure out the correct path for the libxml2 headers using xcrun

gem install libxml-ruby -v '3.2.1' -- --with-xml2-include=`xcrun --show-sdk-path`/usr/include/libxml2

All credit to @CodingMarkus and @raldred for their comments on the Twilio issue #315