The Dangers of a “Walled Garden”
No one seriously argues against the viewpoint that Apple’s OS X provides
developers with a walled garden. While OS X runs Darwin under
the hood, it’s still very much a closed ecosystem. Even if you install
some third-party tools such as MacPorts or Homebrew, you’re
still fundamentally stuck with some of the options that Apple makes on
your behalf, very often in a “take it or leave it” way.
In the case of RVM, Ruby, and RubyGems, the walled garden has been
systematically weeding out standard compilers in favor of
LLVM-based compilers as provided by the 4.x series of Xcode.
In practice, that means many rubies and gems will not compile without
jumping through hoops—and sometimes not even then. Even versions of
Ruby that will compile with LLVM may require gems that won’t, so this is
a non-starter for serious Ruby or Ruby on Rails development.
Luckily, even if you use a Mac on a regular basis, there’s hope. With a
little help from MacPorts, VirtualBox, and some exported compiler
settings, you can get a minimal Ruby environment running well enough to
bootstrap a Linux virtual machine that “just works” for Ruby