Thanks Towo.
1. You have not pasted the whole output! What you have pasted will always show.
Sorry, I thought the mistake would be enough. Here is the full compilation output:
https://pastebin.com/79vTkPDp2. If that is the only error, you don't have the kernel-headers installed on your system.
Yes, I have
aptitude search ~ilinux-headers
idA linux-headers-5.10.0-7-amd64 - Header files for Linux 5.10.0-7-amd64
idA linux-headers-5.10.0-7-common - Common header files for Linux 5.10.0-7
i A linux-headers-5.10.0-8-amd64 - Header files for Linux 5.10.0-8-amd64
i A linux-headers-5.10.0-8-common - Common header files for Linux 5.10.0-8
i A linux-headers-5.10.20-towo.1-si - Header files for Linux 5.10.20-towo.1-sidu
idA linux-headers-5.13.7-2-siductio - Header files for Linux 5.13.7-2-siduction-
i A linux-headers-5.13.8-1-siductio - Header files for Linux 5.13.8-1-siduction-
i linux-headers-amd64 - Header files for Linux amd64 configuration
i linux-headers-siduction-amd64 - Linux headers for siduction on 64-bit PCs
3. That driver will need patched for working with recent kernels.
Many patches are applied automatically on installation, but that's probably the problem. I've been searching without much luck, I'll keep looking to see if I find something.
You really should think about new graphics card, with suck old hardware you will not get lucky in soon time.
Of course, I am aware of it, but it is a laptop that still works very well (Toshiba Satellite A660-1EQ with i7 processor and 8GB of RAM)
Thank you very much for your interest