X/sys: does it support linux/sparc64?

Howdy all!

I’ve come with a question. Whenever I try building x/sys on linux/sparc64 (with gccgo-12 ofc, as that’s the only supported compiler) I get this error:

golang.org/x/sys/cpu
golang.org/x/sys/unix
# golang.org/x/sys/cpu
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20200615200032-f1bc736245b1/cpu/cpu.go:17:30: error: reference to undefined name ‘cacheLineSize’
   17 | type CacheLinePad struct{ _ [cacheLineSize]byte }
      |                              ^
github.com/matrix-org/dendrite/cmd/kafka-producer
# golang.org/x/sys/unix
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20200615200032-f1bc736245b1/unix/dirent.go:16:12: error: reference to undefined name ‘isBigEndian’
   16 |         if isBigEndian {
      |            ^

Looking through the source for x/sys, I see several mentions of sparc. However, there are files for other arches that aren’t there for sparc.

So, what’s causing the issue? Is it because x/sys doesn’t support sparc64? Is it WIP? If so, what could I do to help x/sys get full sparc support?

Or, is this some problem with gccgo(which is behind on features compared to gc) or something wonk with my system?

I appreciate your time :^D