[binarycrusader]

  There I would like that at least they support
  "Bounds-checking interfaces (Annex K)" from C11,
  which is optional.

The bounds-checking interfaces are really something that has to be provided by libc, so Solaris itself will provide those.

Although it isn't highlighted in the release notes in an obvious way, most of the support for C11 is also available in the 12.4 release of the Solaris Studio compiler. The primary things missing are the same things they don't have for C++11: concurrency and atomic primitives.