With Mavericks Apple has removed gcc from the command line developer tools (it is now clang just symlinked to gcc).
In order to get the go 1.1.2 source to compile I had to install gcc on my Mavericks machine, since it was failing with clang.
Here's what I did to get it working
First I installed gcc via homebrew:
# installing gcc on mavericks using brew
brew tap homebrew/dupes
brew install apple-gcc42
Then I symlinked the newly installed apple-gcc42 into my /usr/bin folder
sudo mv gcc gcc_mavs
sudo ln -s /usr/local/Cellar/apple-gcc42/4.2.1-5666.3/bin/gcc-4.2 gcc