QuoteDoes anyone knows whether nVidia (or any other company) holds any claim/patent on FXT1?

FXT1 is the property of nVidia but doesn't require any license for use and is royalty free, it is open source, so you can use it without having to worry about any patent infringement.
Intel is using the GL_3DFX_texture_compression_FXT1 extension for their integrated chipsets.

QuotePS: specific texture compression is still on debate, because of possible legal issues.

Does this mean no support for GL_EXT_texture_compression_s3tc and GL_3DFX_texture_compression_FXT1 ?

QuoteLet's make things clear: no texture compression algorithm will go into Mesa at this stage!

So games which require S3TC won't work or is there a workaround to convert S3TC calls into something else?

QuoteThe real-time compression/decompression will be done -- at best -- through a very special Glide3 library, with embedded Texus2.  Bwahahahahaha! This way, you'll have to use our Glide3 at SourceForge.net!

Could you please elaborate on this?
What is Texus2?