yaml-cpp: fix build with clang 16

[wegank]

Description of changes

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[OPNA2608]

Tested with yaml-cpp.override { stdenv = llvmPackages_16.stdenv; } on x86_64-linux.

Before:

[ 64%] Building CXX object test/prefix/googlemock/CMakeFiles/gmock.dir/src/gmock-all.cc.o
In file included from /build/source/test/gtest-1.10.0/googlemock/src/gmock-all.cc:39:
In file included from /build/source/test/gtest-1.10.0/googlemock/include/gmock/gmock.h:59:
/build/source/test/gtest-1.10.0/googlemock/include/gmock/gmock-actions.h:455:3: error: definition of implicit copy constructor for 'PolymorphicAction<testing::internal::ReturnNullAction>' is deprecated because it has a user-declared copy assignment operator [-Werror,-Wdeprecated-copy]

After: Build is fixed.

LGTM.

[wegank]

Closed by #249947.