The recommended OS to build OpenIndiana on will always be the latest development release at the time you are building. The exception to the OS rule is for bootstrapping OpenIndiana from OpenSolaris where you should have the latest development binary release (b134) installed which can be obtained from Genunix (in case you want to upgrade an older OpenSolaris install to b134, follow 'How to upgrade to snv_134' on IllomOS.
The recommended build environment uses a patched Sun Studio version 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:
Use the Sep 2009 download link for Sun Studio 12 here
Use the February 2010 download link for Sun Studio 12u1 here
Note: Sun Studio 12.2 is available but has not been tested so please do not use at this time.
Get GCC 3.4.3:
pkg install developer/gcc-3
Get CBE 1.7.0 from:
svn co svn+ssh://firstname.lastname@example.org/svn/jds/jds-cbe/trunk jds-cbe
CBE source browser
Get GNU gettext 0.16.1 or higher: