[NFC] Disable a warning that happens on system headers on CI

[kripken]

CI started to error here, after some infra changes apparently:

https://github.com/WebAssembly/binaryen/actions/runs/9099538230/job/25012304693

In file included from /home/runner/work/binaryen/binaryen/src/passes/StringLowering.cpp:33:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/algorithm:61:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/stl_algo.h:61:
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/stl_tempbuf.h:263:8: error: 'get_temporary_buffer<std::unique_ptr<wasm::Global>>' is deprecated [-Werror,-Wdeprecated-declarations]
  263 |                 std::get_temporary_buffer<value_type>(_M_original_len));

      |                      ^

/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/stl_algo.h:4996:15: note: in instantiation of member function 'std::_Temporary_buffer<__gnu_cxx::__normal_iterator<std::unique_ptr<wasm::Global> *, std::vector<std::unique_ptr<wasm::Global>>>, std::unique_ptr<wasm::Global>>::_Temporary_buffer' requested here
 4996 |       _TmpBuf __buf(__first, (__last - __first + 1) / 2);
      |               ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/stl_algo.h:5070:23: note: in instantiation of function template specialization 'std::__stable_sort<__gnu_cxx::__normal_iterator<std::unique_ptr<wasm::Global> *, std::vector<std::unique_ptr<wasm::Global>>>, __gnu_cxx::__ops::_Iter_comp_iter<(lambda at /home/runner/work/binaryen/binaryen/src/passes/StringLowering.cpp:174:7)>>' requested here
 5070 |       _GLIBCXX_STD_A::__stable_sort(__first, __last,
      |                       ^
/home/runner/work/binaryen/binaryen/src/passes/StringLowering.cpp:171:10: note: in instantiation of function template specialization 'std::stable_sort<__gnu_cxx::__normal_iterator<std::unique_ptr<wasm::Global> *, std::vector<std::unique_ptr<wasm::Global>>>, (lambda at /home/runner/work/binaryen/binaryen/src/passes/StringLowering.cpp:174:7)>' requested here
  171 |     std::stable_sort(
      |          ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/stl_tempbuf.h:99:5: note: 'get_temporary_buffer<std::unique_ptr<wasm::Global>>' has been explicitly marked deprecated here
   99 |     _GLIBCXX17_DEPRECATED
      |     ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/x86_64-linux-gnu/c++/12/bits/c++config.h:119:34: note: expanded from macro '_GLIBCXX17_DEPRECATED'
  119 | # define _GLIBCXX17_DEPRECATED [[__deprecated__]]
      |                                  ^

[kripken]

Trying to skip the include line that errored did not help as it errored on the next place to include it.

It seems like this is a new warning in clang that is firing on system headers, so I'm not sure if we can do anything aside from disable the warning, which I pushed now, or bundle our own libc++. This PR now disables the warning.

[tlively]

Should we put this in the cmake config instead? That would prevent the error from affecting anyone locally, too.

[kripken]

Well, I don't know if this is some weird thing on the CI machines. We've never gotten a report of this before til CI started to error.

If this is just CI picking up on an update to some common distro then maybe we should. But I'm not sure how to check that. The readme file that tracks what ubuntu-latest means does not indicate a major upgrade recently, it's been 22.04 for a while. With that said there was a minor update recently, which apparently removed "GNU C++"...?

[kripken]

But I guess it's such an unimportant warning we can just do it in cmake, to be safe. Done.