How to use RVM to install Ruby 1.9.3 when Xcode 4.3.2 is installed and gcc is missing?

I got a new iMac with Lion and installed Xcode 4.3.2. After running

curl -L get.rvm.io | bash -s stable

I opened up a new bash, and used

$ rvm install 1.9.3

to install Ruby 1.9.3, but there were errors and the log said that the C compiler is not there. And rvm requirements says:

$ rvm requirements
  [...]
Xcode 4.3+ users
- please be warned
- only ruby-1.9.3-p125+ is partially supported
- in case of any compilation issues:
 * downgrade to Xcode 4.1
 * uninstall Xcode and install osx-gcc-installer
and reinstall your rubies.

So does that mean I might need to downgrade to Xcode 4.1? What if I want to keep Xcode 4.3.2? Then will 1.9.3-p125+ be able to work, but only partially?

Update: or how about installing Ruby 1.9.2 -- will it work with the latest Rails 3.2.3? If so, how to add gcc? (using Xcode's gcc?)

To install 1.9.2 or lower you need to follow the instructions in this blog post. It outlines how it get a copy of GCC which does not conflict with Xcode but can be used to build Ruby.

Xcode 4.3, Homebrew and Ruby.

You cannot install the osx-gcc-installer as it will conflict with Xcode 4.3.2, overwriting the working versions of llvm-gcc and clang.

install osx-gcc-installer

use latest ruby: