Is it a patent for a hrdware solution, or for software? If software then in Europe, at least in Germany and others, it wouldn't matter because softwarepatents are not possible (and hopefully never will).
Well, since the demise of S3 (I do not remember who bought the name) the status of the patent is unclear (from what I heard, nobody really knows a lot whom to contact to get any details).
But well, either it's a hardware only patent and, in Wine, we have no issues at all. Either it's a software + hardware patent and we can use the code in Wine in Europe.
Our plans to support this was to write some library (shipped outside of Wine of course) that would be dlopened at run time and provide S3TC decompression. Note that, in the D3D7 code, we first need to do some basic ground-work to support this (the main blocking point is not really S3TC for now).
Lionel