The words "executable runtime" are not present in the text of the GPL. What the GPL *does* say is that kernels are only exempted from being considered part of the GPL definition of source code for a work *if* the GPLed work is not distributed together with the kernel.
I think you're stretching the definition of "distributed together" somewhat, in an effort to exclude all non-GPL software from any GNU/* operating system. That's not what the GPL intends:
GPL: """The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable."""
What this says is if I distribute an application A whose source code is licensed under the GPL, then I must also distribute the source code for that application. If the application A is provided along with the major components of the operating system it runs on, then I must provide the source code for those components as well.
In other words, if the only means to deploy application A is via something like a "live" Linux CD, then I have to also provide the source code for the GPL major components that application A depends on as they appear on that CD (kernel, compiler, C runtime library, etc.) so that the user could reconstruct the CD as needed to redeploy the application.
If application A is deployed as a standalone application built using the major components of the target operating system, a'la a Debian package, I don't have to provide source code for anything other than the application itself.
Furthermore, the GPL's "mere aggregation" clause allows for non-GPL applications to run in GPL operating systems. As an example, the Linux kernel and userland applications clearly have a distinct identity and can exist independently of each other; thus, their coexistence is defined by the GPL to be mere aggregation, and the license status of either party does not in isolation affect the license status of the other.
Assuming you use glibc and other GNU-license-compatible runtime libraries, mere aggregation allows for a Debian userland under even a closed-source kernel (which would be an extreme interpretation of the Solaris license). Thus, I don't see a problem here.
b.g. -- Bill Gatliff bgat@billgatliff.com