cc-wrapper: disable POSIX compatibility

[abbradar]

Motivation for this change

When POSIXLY_CORRECT environment variable is set the script runs in sh compatibility mode, which fails because we use process piping in utils.sh. This patch explicitly disables POSIX compatibility mode.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

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Checked by unsafe editing of script in Nix store and running the compiler on configure script which mysteriously failed before.

[Ericson2314]

You should make the same change in ld-wrapper.sh, but +1 on concept.

[abbradar]

@Ericson2314 fixed!

EDIT: Fixed also for GNAT.

[edolstra]

I don't understand the motivation. Where are we setting POSIXLY_CORRECT? Why do we suddenly need to disable POSIX compatibility, whatever that is?

[abbradar]

@edolstra A random configure script that I encountered sets POSIXLY_CORRECT environment variable and then runs GCC. Turns out bash reacts to that variable and turns POSIX compatibility mode (think sh instead of bash -- no Bash extensions) by default, which breaks our script. This patch explicitly always disables this compatibility mode, just in case.

P.S. I have no idea what Bash developers were thinking when they allowed an environment variable to change how a script is evaluated but oh well.

[abbradar]

I'll merge this in several days if noone objects, preferrably after current staging gets in master so that I can proceed with #30433 and related work.

[orivej]

This is the third known case of POSIXLY_CORRECT or set -o posix causing trouble, the previous was in #28255 (comment)

[abbradar]

I wanted to merge this with several additional wrapper patches but I still need to work on them some more. Feel free to batch this together with any mass rebuild change!

[dezgeg]

There's one gawk update right now, taking with it.