[georgemcbay]

Even if you don't make changes to the compiler, if you link to this project you are GPLv3 infected. You simply can't use this without exposing your entire project to GPLv3 infection, the usual LGPL and/or runtime library exceptions don't apply to gcc's core code because it was never intended to be used as a library.

Let's say you have an existing FOSS app that is BSD or MIT licensed and it has its own built-in scripting language. You'd like to build a JIT for that scripting language, you see this library and decide to use it in your project, well... you can't do that without changing your entire project to GPLv3 terms because the combined work created between this and your own code all has to be available under the GPLv3 terms. This is usually solved by making the relevant parts of the project LGPL or granting a runtime library exception but neither of those applies to the core gcc code, so the GPLv3 infection in unavoidable.

Whether or not that issue is important is open to debate and depends upon your software politics, but in practical terms it means very few people will use this in their project unless they are already GPLv3 committed for some reason.