src: update node.cc and related for z/OS

[gabylb]

Updates here apply to z/OS only.

• Add new src/node_zos.h and src/node_zos.cc, used by src/node.cc.
• Add new src/zos_setlibpath.cc and link its .o directly into node so the __setlibpath object's constructor finds libnode.so and add its path to LIBPATH, so it can be loaded.
• Pass '-Wl,-bedit=no' when linking libnode.so to reduce its size.
• Use z/OS specific signal handling logic, as signals on z/OS must be handled in a dedicated thread.
• Force V8 flag --nohard_abort due to absence of XPLINK headers in JS generated code.
• Include display of zoslib build version.

[nodejs-github-bot]

Review requested:

• @nodejs/gyp
• @nodejs/startup

[inoway46]

Thanks for working on this! The commit and lint checks are currently failing. Have you also verified that this builds successfully locally?

Please follow the guide below:
https://github.com/nodejs/node/blob/main/doc/contributing/pull-requests.md

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.43%. Comparing base (60c7958) to head (36e2894).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66569      +/-   ##
==========================================
- Coverage   92.77%   90.43%   -2.34%     
==========================================
  Files         422      791     +369     
  Lines      193594   276487   +82893     
  Branches    29857    53088   +23231     
==========================================
+ Hits       179604   250053   +70449     
- Misses      13662    16847    +3185     
- Partials      328     9587    +9259     

Files with missing lines	Coverage Δ
src/node.cc	79.24% <ø> (ø)

... and 498 files with indirect coverage changes

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[gabylb]

Thanks for working on this! The commit and lint checks are currently failing. Have you also verified that this builds successfully locally?

Please follow the guide below: https://github.com/nodejs/node/blob/main/doc/contributing/pull-requests.md

Hello Yuya. This PR is part of a number of PRs to be opened for the z/OS port; in our environment, which includes all the port, node builds successfully.

[addaleax]

A lot of these changes could use comments that explain why specifically z/OS needs these and other OSes don't – e.g. SA_ONSTACK and SA_SIGINFO aren't z/OS-specific per se, so it's not obvious why the conditional is here (I might guess because of SIGABRT being listed below as a handled signal – but let's not have this be a silent assumption?)

[gabylb]

Please see https://www.ibm.com/docs/en/zos/3.1.0?topic=functions-sigaction-examine-change-signal-action.
For SA_SIGINFO, sa_sigaction is specified for the sigaction() call here. For SA_ONSTACK, it's to use the alternate signal stack created initially in zosStart(), to not interfere with the z/OS Language Environment runtime environment.

Would you like such comments added in the code, or in the commit's message?