Despite good intentions, support for GNAT-AUX/GCC-AUX had never been added to pkgsrc. The reason is that multilib support was desired (this means x86-64 Solaris can build 32-bit executables), but all builds failed on the Ada libraries on gcc 4.7.x. It turns out that this was a reported bug and it has since been fixed.

Happily a multilib-capable x86-64 bootstrap compiler was created on OmniOS. After some tweaking, pkgsrc is now capable of building gcc 4.9.0 i386 compilers (demonstrated on Joyent's SmartOS development server) and new x86-64 compilers on OmniOS.

This has not been tested on Solaris 10 or Solaris 11 yet, but it is not expected to work as the bootstrap is dynamically linked to system libraries (static linking is no longer possible since Solaris 9). There could be symbols created by Illumos that Solaris 10/11 don't understand. If that is the case, another bootstrap compiler specifically for Solaris 10/11 will be required for those platforms.

After pkgsrc branches its next quarterly, Joyent will start producing binary packages of gcc-aux which can be used on any Illumos distribution. Otherwise any installation of pkgsrc on an Illumos platform can build it from source right now.

By the way, it passed both testsuites perfectly. It's a reliable compiler!