These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.57 s (backtrack: 0/20).

[ebuild  N     ] sys-process/numactl-2.0.19::gentoo  USE="-static-libs" 441 KiB
[ebuild     U  ] x11-libs/libdrm-2.4.134::gentoo [2.4.131::gentoo] USE="-doc -test -tools -udev -valgrind" VIDEO_CARDS="amdgpu* vmware (-exynos) (-freedreno) -intel -nouveau (-omap) -radeon (-tegra) (-vc4) (-vivante)" 427 KiB
[ebuild  N     ] dev-libs/roct-thunk-interface-7.1.0:0/7.1::gentoo  USE="-test" LLVM_SLOT="20" 2250 KiB

Total: 3 packages (1 upgrade, 2 new), Size of downloads: 3117 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by dev-libs/roct-thunk-interface-7.1.0::gentoo
# required by =dev-libs/roct-thunk-interface-7.1.0 (argument)
>=x11-libs/libdrm-2.4.134 video_cards_amdgpu