build failure in libdrm-2.4.20 on 5.0_STABLE/i386

[denbrok%uni-bonn.de@localhost]

Hello,

I'm getting the following error when building libdrm using pbulk
on 5.0_STABLE/i386:

In file included from intel_bufmgr_gem.c:42:
../xf86atomic.h:96:2: error: #error libdrm requires atomic operations, please 
define them for your CPU/c
ompiler.

How to fix this?

TIA,

Dennis den Brok