Fix undefined symbol errors on building otelcorecol for Plan 9

[lufia]

Description:

Building otelcorecol was broken for Plan 9.

$ cd cmd/otelcorecol
$ GOOS=plan9 go build
# go.opentelemetry.io/collector/exporter/loggingexporter
../../exporter/loggingexporter/known_sync_error.go:29:10: undefined: syscall.ENOTSUP
../../exporter/loggingexporter/known_sync_error.go:31:10: undefined: syscall.ENOTTY
../../exporter/loggingexporter/known_sync_error.go:33:10: undefined: syscall.EBADF

Testing:
Though I'm not sure yet there are more other issues when otelcorecol is running on Plan 9, at least, this PR is fixed undefined symbol errors and I checked otelcorecol shows a help successfully with -h option.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: lufia / name: KADOTA, Kyohei (c03b161)

[codecov]

Codecov Report

Base: 91.05% // Head: 91.08% // Increases project coverage by +0.03% 🎉

Coverage data is based on head (a8af06c) compared to base (7d168dd).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6924      +/-   ##
==========================================
+ Coverage   91.05%   91.08%   +0.03%     
==========================================
  Files         237      238       +1     
  Lines       14298    14418     +120     
==========================================
+ Hits        13019    13133     +114     
- Misses       1027     1033       +6     
  Partials      252      252              

Impacted Files	Coverage Δ
exporter/loggingexporter/known_sync_error.go	0.00% <ø> (ø)
connector/connector.go	100.00% <100.00%> (ø)
connector/connectortest/connector.go	100.00% <100.00%> (ø)
service/extensions/extensions.go	77.90% <0.00%> (-0.99%)	⬇️
service/pipelines.go	93.93% <0.00%> (-0.30%)	⬇️
service/internal/components/loggers.go	76.00% <0.00%> (ø)

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[mx-psi]

Hey @lufia, thanks for the PR. While we don't currently have a well defined policy on when/how to add support to new OS or architectures, I personally would be fine accepting this change with the understanding that

• we can't ensure we won't break the Plan 9 build in the future
• we probably will not be able to address any bug reports that are Plan 9 specific
• we won't provide official builds or run the test suite on CI for Plan 9
• a Plan 9 build may not have feature parity with our official builds
• If there are issues that interfere with development we may need to remove support for Plan 9 entirely if we don't get help from you or other contributors

(where 'we' here is to be understood as 'the current OTel Collector community')

The above is my personal take on this, other contributors may disagree. I can work on getting agreement from the community and making this informal policy more well defined if this seems acceptable to you.

[lufia]

Hi @mx-psi thank you for your review!

I have agree all of them.

I'd like to serve otelcontribcol service in my own Plan 9 box so far. I would make an effort to keep Plan 9 build healthy as far as I possible so please feel free to tell me if someone notices any issues in the future.

[mx-psi]

LGTM 🐰 🧑‍🚀

[lufia]

Thats glenda!

[bogdandrutu]

should this be "other" file and have the rule !linux && !darwin?