Can't install Ruby under Lion with RVM – GCC issues

This answer was edited multiple times and now contains several alternative solutions. Try the simple “Edit 3” solution first.

Ruby 1.9.3-p125 and later have official support for clang, so if you are installing such a version you should not need GCC. If you’re installing an older version of Ruby, read on.

To compile Ruby with GCC, you need a non-LLVM version of GCC, which is no longer included with Xcode 4.2. Install it yourself (or downgrade to Xcode 4.1 temporarily), then do CC=/usr/local/bin/gcc-4.2 rvm install 1.9.3 --enable-shared (substituting the path to your non-LLVM gcc).

Edit: https://github.com/kennethreitz/osx-gcc-installer/downloads may help for installing GCC. There is also some info available by running rvm requirements.

Edit 2: For an easier solution, you can try adding --with-gcc=clang to the arguments to configure for Ruby to use clang instead of GCC.

Edit 3: rvm install 1.9.3 --with-gcc=clang does that for you.

Note: With current versions of Xcode you need to install the command-line tools separately from the Xcode menu -> Preferences -> Downloads -> Components. This is a pre-requisite for doing any compiling with Xcode on the command-line, not just Ruby.

Note 2: If something doesn't work after following the steps, try doing a reboot or re-login to ensure that the environment gets set correctly.

Note 3: Ruby versions prior to 1.9.3-p125 may not always be fully compatible with clang, so test your software thoroughly if using the “edit 3” solution in a production environment.

SUMMARY FOR STACK OVERFLOW

I was trying to install SiriProxy on a clean Lion installation on Xcode from App Store

I kept getting errors like : The provided CC(/usr/bin/gcc) is LLVM based.

bash-3.2$ rvm install 1.9.3
ERROR: The provided CC(/usr/bin/gcc) is LLVM based, it is not yet fully supported by ruby and gems, please read `rvm requirements`.

After 2 days finally got it working with these two lines:

http://stackoverflow.com/questions/8000145/ruby-rvm-llvm-and-mysql

bash-3.2$ rvm get head
bash-3.2$ CC=/usr/bin/gcc-4.2 rvm install 1.9.3 --enable-shared

Before that I had tried every stackoverflow article on Ruby and Lion so doing these may have done some setup that helped the above 2 steps work:

Things I tried included:

Running Install Xcode.app (I had downloaded from App Store - running this does futher installation)

Installing

https://github.com/kennethreitz/osx-gcc-installer/downloads may help for installing GCC.

Set up CC in

more /Users//.bash_profile

bash-3.2$ more /Users/<USERNAME>/.bash_profile 
[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # Load RVM function
export CC=/usr/share/TargetConfigs/bin/gcc

First line came from SiriProxy install instruction https://github.com/plamoni/SiriProxy

2nd line export CC never seemed to work. So dont add.

It had many versions each pointing I finally used CC=/usr/bin/gcc-4.2 rvm install 1.9.3 --enable-shared

rvm install 1.9.3 --with-gcc=clang

Worked for me. This was on a brand new Lion with Xcode (had no "traditional" GCC).