This is a dump of the error from puppet/Vagrant that our Mac developers are getting when using Vagrant with VMWare Fusion. The problem is resolvable by changing rbenv's cflags to none.

Rbenv failing on Vagrant+Fusion

Notice: /Stage[main]//Rbenv::Plugin[sstephenson/ruby-build]/Exec[install-sstephenson/ruby-build]/returns: executed successfully
Notice: /Stage[main]//Rbenv::Plugin[sstephenson/ruby-build]/Exec[rbenv-permissions-sstephenson/ruby-build]: Triggered 'refresh' from 1 events
Notice: /Stage[main]/Rbenv/File[/etc/profile.d/rbenv.sh]/ensure: defined content as '{md5}1895fedb6a7fdc5feed9b2cbbb8bbb60'
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[own-plugins-2.0.0-p247]/returns: executed successfully
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[git-pull-rubybuild-2.0.0-p247]/returns: executed successfully
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: Downloading ruby-2.0.0-p247.tar.gz...
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: -> http://dqw8nmjcqpjn7.cloudfront.net/c351450a0bed670e0f5ca07da3458a5b
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: Installing ruby-2.0.0-p247...
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns:
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: BUILD FAILED
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns:
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: Inspect or clean up the working tree at /tmp/ruby-build.20140103160549.12788
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: Results logged to /tmp/ruby-build.20140103160549.12788.log
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns:
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: Last 10 log lines:
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: compiling util.c
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: compiling variable.c
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: /tmp/ccTqc9bY.s: Assembler messages:
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: /tmp/ccTqc9bY.s:1634: Error: no such instruction: `vfnmadd312sd .LC14(%rip),%xmm0,%xmm2'
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: make: *** [time.o] Error 1
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: make: *** Waiting for unfinished jobs....
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: /tmp/ccMLOibd.s: Assembler messages:
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: /tmp/ccMLOibd.s:6960: Error: no such instruction: `vfmadd312sd .LC20(%rip),%xmm0,%xmm2'
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: /tmp/ccMLOibd.s:7133: Error: no such instruction: `vfmadd312sd .LC20(%rip),%xmm0,%xmm3'
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-install-2.0.0-p247]/returns: make: *** [util.o] Error 1
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-ownit-2.0.0-p247]: Dependency Exec[rbenv-install-2.0.0-p247] has failures: true
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Exec[rbenv-global-2.0.0-p247]: Dependency Exec[rbenv-install-2.0.0-p247] has failures: true
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Rbenv::Gem[bundler-2.0.0-p247]/Exec[gem-install-bundler-2.0.0-p247]: Dependency Exec[rbenv-install-2.0.0-p247] has failures: true
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Rbenv::Gem[bundler-2.0.0-p247]/Exec[rbenv-rehash-bundler-2.0.0-p247]: Dependency Exec[rbenv-install-2.0.0-p247] has failures: true
Notice: /Stage[main]//Rbenv::Build[2.0.0-p247]/Rbenv::Gem[bundler-2.0.0-p247]/Exec[rbenv-permissions-bundler-2.0.0-p247]: Dependency Exec[rbenv-install-2.0.0-p247] has failures: true