ci: build riscv64 binaries

[ernado]

Add linux/riscv64 target, alongside with linux/s390x, linux/ppc64, ..., etc.

I've failed to found where to add linux/riscv64 in this repo, so can't issue a PR.

I've checked it manually:

ernado@nexus:/src/node_exporter$ GOARCH=riscv64 make build
>> building binaries
/go/bin/promu --config .promu.yml build --prefix /src/node_exporter 
 >   node_exporter
ernado@nexus:/src/node_exporter$ scp node_exporter riscv:~
node_exporter 

root@starfive:~# uname -a
Linux starfive 5.15.0-starfive #1 SMP Mon Feb 27 14:03:14 EST 2023 riscv64 GNU/Linux
root@starfive:~# ./node_exporter 
ts=2023-04-01T08:58:29.488Z caller=node_exporter.go:180 level=info msg="Starting node_exporter" version="(version=1.5.0, branch=master, revision=6a42c0b0a82caa3bf9526bc80d86f8f5550bf84e)"
ts=2023-04-01T08:58:29.488Z caller=node_exporter.go:181 level=info msg="Build context" build_context="(go=go1.20.2, platform=linux/riscv64, user=ernado@nexus, date=20230401-08:55:10)"
...

root@starfive:~# curl -sNL 0.0.0.0:9100/metrics | head 
# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
# TYPE go_gc_duration_seconds summary
go_gc_duration_seconds{quantile="0"} 9.9751e-05
go_gc_duration_seconds{quantile="0.25"} 9.9751e-05
go_gc_duration_seconds{quantile="0.5"} 9.9751e-05
go_gc_duration_seconds{quantile="0.75"} 9.9751e-05
go_gc_duration_seconds{quantile="1"} 9.9751e-05
go_gc_duration_seconds_sum 9.9751e-05
go_gc_duration_seconds_count 1
# HELP go_goroutines Number of goroutines that currently exist.

Works fine on StarFive VisionFive 2.

[discordianfish]

Targets are configured here (if CGO is needed): https://github.com/prometheus/node_exporter/blob/master/.promu-cgo.yml#L23
..or if it isn't: https://github.com/prometheus/node_exporter/blob/master/.promu.yml#L22

[dswarbrick]

@ernado In case you are running Debian bookworm / sid, node_exporter is provided for riscv64 in the sid repos: https://packages.debian.org/sid/riscv64/prometheus-node-exporter/download

riscv64 is an unofficial arch on Debian, which means it is not yet shipped with any official releases. However, any packages that land in sid will automatically attempt to build on riscv64, most of the time successfully.

[ernado]

Should I close this issue until riscv64 will be supported by Debian or just leave it until then?

[discordianfish]

Let's keep it open, if we can easily cross compile for these archs we should provide them

[dongjiang1989]

Makefile.common need update promu version to 0.15.0 , auto support

[SuperQ]

Done: #2752