Fix building on Linux 6.15

[Prince213]

EXTRA_CFLAGS is no longer supported, use ccflags-y instead. (See kernel documentation for v6.14 and v6.15)

Related:

• oct612x: Use ccflags-y instead of EXTRA_CFLAGS. asterisk/dahdi-linux#77
• morrownr/rtl8852bu-20240418@42de963

Downstream issue: NixOS/nixpkgs#412107

[tomaspinho]

Thanks for this @Prince213. However, before merging, we'll need to find a way to make this backwards-compatible. Ubuntu LTS is on <= 6.12 and I don't want us to break everyone else 😄

[Prince213]

Hi @tomaspinho, ccflags-y has been introduced since 2007 in torvalds/linux@f77bf01425b11947eeb3b5b54 and the timer_delete_sync change is guarded. Do you have specific lines of change in mind that you feel won't be backwards-compatible?

[tomaspinho]

The snapshot this module tree is based on is much more recent than 2007, it's from 2017-2018. So I'm surprised Realtek wasn't using the newer variable at the time.

Anyway, would you be able to test a build of your branch for 6.12 or 6.10? Just for us to be extra careful. Thanks!

[Prince213]

Nixpkgs don't have linux 6.10 as it has already reached EOL, so I tested building for 6.12 both locally and on CI and it builds without issue.

CI logs: https://logs.ofborg.org/?key=nixos/nixpkgs.412744&attempt_id=57d44928-45b7-411b-8848-a30627fb08be.

[tomaspinho]

Thanks for testing it! Merging.

[Prince213]

Thanks!