The recommended build environment uses a patched Sun Studio 12 to compile along side a patched Sun Studio 12.1 to provide the lint. Both compilers are available to download as tarballs from here:
These links are no longer active. Oracle has removed these packages from public view.
If the links - provided above - are inactive, you can download from Oracle's official site:
Make sure your regular user account has "pkg install/uninstall" privilege in /etc/user_attr.