subprocess: replace USING_WINDOWS with WIN32 #34733

1. 
   kevkevinpal commented at 4:10 pm on March 4, 2026: contributor

   Summary

   Motivated by #34385#pullrequestreview-3826616188

   In subprocess.h we are now renaming __USING_WINDOWS__ with WIN32

   In the rest of the codebase, we are using WIN32, so it makes sense to update subprocess.h to match that.

   ---

   Use the following grep to assert there is no __USING_WINDOWS__ in the codebase

   0grep -nri --exclude-dir=build "WIN32" ./ -I
   1rep -nri --exclude-dir=build "__USING_WINDOWS__" ./ -I
   

2. subprocess: replace __USING_WINDOWS__ with WIN32 bff8a7a80d
3. 
   DrahtBot commented at 4:11 pm on March 4, 2026: contributor

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4. sedited approved
5. 
   sedited commented at 10:24 am on March 5, 2026: contributor

   ACK bff8a7a80d2a198e84443a696438925d4c303c7b
6. sedited requested review from hebasto on Mar 5, 2026
7. 
   hebasto commented at 11:30 am on March 5, 2026: member

   Concept ACK on diverting from the upstream project for the following reasons:

   1. It targets C++11, whereas we are using C++20.
   2. We only need a subset of its functionality.
8. hebasto approved
9. 
   hebasto commented at 11:34 am on March 5, 2026: member

   ACK bff8a7a80d2a198e84443a696438925d4c303c7b, I have reviewed the code and it looks OK.
10. hebasto merged this on Mar 5, 2026
11. hebasto closed this on Mar 5, 2026

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Contributors
kevkevinpal DrahtBot sedited hebasto