pkg/56480: Some drivers from meta-pkgs/modular-xorg-drivers fail to build on Linux aarch64 platform

[cryintothebluesky%gmail.com@localhost]

>Number:         56480
>Category:       pkg
>Synopsis:       Some drivers from meta-pkgs/modular-xorg-drivers fail to build on Linux aarch64 platform
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Oct 31 08:25:01 +0000 2021
>Originator:     Sad Clouds
>Release:        pkgsrc-2021Q3
>Organization:
>Environment:
Linux rp4 5.10.0-0.bpo.8-arm64 #1 SMP Debian 5.10.46-4~bpo10+1 (2021-08-07) aarch64 GNU/Linux
>Description:
Some xorg drivers use inb() and outb() functions that don't exist on aarch64. This results in the following errors:

error: implicit declaration of function 'inb' [-Werror=implicit-function-declaration]
error: implicit declaration of function 'outb' [-Werror=implicit-function-declaration]

On x86 Linux these functions are defined in /usr/include/x86_64-linux-gnu/sys/io.h

inb (unsigned short int __port)
  __asm__ __volatile__ ("inb %w1,%0":"=a" (_v):"Nd" (__port));

This functionality is missing on aarch64
>How-To-Repeat:

>Fix:
Change meta-pkgs/modular-xorg-drivers/Makefile and don't build the following drivers on non-x86 platforms:

xf86-video-siliconmotion-[0-9]*:../../x11/xf86-video-siliconmotion
xf86-video-tseng-[0-9]*:../../x11/xf86-video-tseng
xf86-video-xgi-[0-9]*:../../x11/xf86-video-xgi