antlr3: make C++ includes compatible with C++20

[cmm]

(by stealing the relevant patch from Fedora)

Motivation for this change

upstream does not compile with C++20

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• 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 nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[r-rmcgibbo]

Result of nixpkgs-review pr 120234 at 2ea89de2 run on aarch64-linux 1

1 package built successfully:

• antlr3 (antlr3_5)

2 suggestions:

• warning: missing-phase-hooks

  installPhase should probably contain runHook preInstall and runHook postInstall.

  Near pkgs/development/tools/parsing/antlr/3.5.nix:24:3:

     |
  24 |   installPhase = ''
     |   ^
  

• warning: missing-patch-comment

  Please add a comment on the line above, explaining the purpose of this patch.
  Near pkgs/development/tools/parsing/antlr/3.5.nix:18:5:

     |
  18 |     (fetchurl {
     |     ^
  

---

Result of nixpkgs-review pr 120234 at 2ea89de2 run on x86_64-linux 1

1 package built successfully:

• antlr3 (antlr3_5)

2 suggestions:

• warning: missing-patch-comment

  Please add a comment on the line above, explaining the purpose of this patch.
  Near pkgs/development/tools/parsing/antlr/3.5.nix:18:5:

     |
  18 |     (fetchurl {
     |     ^
  

• warning: missing-phase-hooks

  installPhase should probably contain runHook preInstall and runHook postInstall.

  Near pkgs/development/tools/parsing/antlr/3.5.nix:24:3:

     |
  24 |   installPhase = ''
     |   ^