Tests failing in Linux: Package xkbcommon-x11 not found

[Deleplace]

What are you trying to do?

Checkout Gonum, run all the tests

What did you do?

$ go test ./...

What did you expect to happen?

OK

What actually happened?

$ go test ./...
go: downloading gioui.org v0.0.0-20210308172011-57750fc8a0a6
go: downloading golang.org/x/sys v0.0.0-20210304124612-50617c2ba197
ok  	gonum.org/v1/plot	0.434s
ok  	gonum.org/v1/plot/cmpimg	0.948s
ok  	gonum.org/v1/plot/font	0.051s
?   	gonum.org/v1/plot/font/liberation	[no test files]
ok  	gonum.org/v1/plot/gob	0.086s
ok  	gonum.org/v1/plot/palette	0.168s
?   	gonum.org/v1/plot/palette/brewer	[no test files]
ok  	gonum.org/v1/plot/palette/moreland	2.450s
# pkg-config --cflags  -- egl wayland-egl wayland-client wayland-cursor x11 xkbcommon xkbcommon-x11 x11-xcb xcursor xfixes
Package xkbcommon-x11 was not found in the pkg-config search path.
Perhaps you should add the directory containing `xkbcommon-x11.pc'
to the PKG_CONFIG_PATH environment variable
No package 'xkbcommon-x11' found
pkg-config: exit status 1
ok  	gonum.org/v1/plot/plotter	10.454s
...
...
FAIL

What version of Go and Gonum/plot are you using?

$ go version
go version go1.16 linux/amd64
$ git rev-parse HEAD
caab7788e04dfd7a74cec4ee80f55b7d1f9a2bfa

This is Gonum v0.9.0

Does this issue reproduce with the current master?

Yes

[Deleplace]

What I had in mind is listing the required dependencies in README.md

[kortschak]

That sounds like a good idea. You can see what those are from the CI configuration, here.