Add klogctl to linux and android

[sgasse]

Those are useful to read the kernel message buffer.

References:

• https://android.googlesource.com/platform/bionic/+/master/libc/include/sys/klog.h
• https://man7.org/linux/man-pages/man2/syslog.2.html

[rustbot]

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[sgasse]

@rustbot author

[sgasse]

Dear reviewer, some notes 🙂

• klogctl is used in some android native binaries but also exists for linux.
• The KLOG_* constants are only defined in user space on android.
  • man7 also describes those constants as SYSLOG_ACTION_* for linux, however that does not seem to be the case on every linux machine. CI fails finding them and on my (Ubuntu 20.04), the man page says:

  • The type argument determines the action taken by this function. The list below specifies the values for type. The symbolic names are defined in the kernel source, but are not exported to user space; you will either need to use the numbers, or define the names yourself.

CI seems to be green except for the MacOS runs. I did not touch anything MacOS-related, so I would guess the fails are unrelated.

[sgasse]

@rustbot review

[tgross35]

Could you target main please? Otherwise lgtm, with one nit above.

@rustbot label +stable-nominated
@rustbot author

[bors]

☔ The latest upstream changes made this pull request unmergeable. Please resolve the merge conflicts.

[sgasse]

Thank you for the review @tgross35 ! I updated the argument name as suggested in your review. Next I changed the base of the PR to main, rebased locally on upstream/main and pushed it (hopefully not breaking anything and not generating noise due to the base change).

[sgasse]

@rustbot review

[tgross35]

Thanks!