Rebased so Rietveld can work with it, earlier version was my fault.

As far as I can see (looking at Python/random.c and configure.ac), the Solaris version should also use GRND_NONBLOCK:

#ifdef MS_WINDOWS
#elif defined(HAVE_GETENTROPY) && !defined(sun)
#else

#if defined(HAVE_GETRANDOM) || defined(HAVE_GETRANDOM_SYSCALL)
    const int flags = GRND_NONBLOCK;
#ifdef HAVE_GETRANDOM
            n = getrandom(dest, n, flags);
#else
            n = syscall(SYS_getrandom, dest, n, flags);
#endif

Apart from using a C function call versus syscall(), I don’t see there is much difference between the Solaris and Linux cases. Correct me if I’m wrong though.