binaryen does not build with gcc 16 due to -Werror=array-bounds

[whispersofthedawn]

When building binaryen with GCC 16 with the default build configuration, the build fails due to the array-bounds warning being promoted to an error.

Reproduction process:

1. Ensure you have GCC 16. I am using GCC 16.1.0.
2. Check out binaryen at commit a570236 (latest main at time of writing)
3. Configure the project with cmake . from the repository root.
4. Build binaryen with make, and observe the errors that appear.

The errors look like so:

[ 50%] Building CXX object CMakeFiles/binaryen.dir/src/passes/OptimizeForJS.cpp.o
[ 51%] Building CXX object CMakeFiles/binaryen.dir/src/passes/PickLoadSigns.cpp.o
[ 51%] Building CXX object CMakeFiles/binaryen.dir/src/passes/Poppify.cpp.o
[ 51%] Building CXX object CMakeFiles/binaryen.dir/src/passes/PostEmscripten.cpp.o
[ 51%] Building CXX object CMakeFiles/binaryen.dir/src/passes/Precompute.cpp.o
[ 52%] Building CXX object CMakeFiles/binaryen.dir/src/passes/Print.cpp.o
[ 52%] Building CXX object CMakeFiles/binaryen.dir/src/passes/PrintBoundary.cpp.o
In file included from /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/stl_iterator.h:78,
                 from /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/ranges_base.h:39,
                 from /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/ranges_util.h:34,
                 from /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/tuple:46,
                 from /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/functional:71,
                 from /home/whispers/scratchpad/binaryen/src/pass.h:20,
                 from /home/whispers/scratchpad/binaryen/src/ir/module-utils.h:20,
                 from /home/whispers/scratchpad/binaryen/src/passes/PrintBoundary.cpp:54:
In function ‘constexpr void std::destroy_at(_Tp*) [with _Tp = mutex]’,
    inlined from ‘constexpr void std::_Destroy(_Tp*) [with _Tp = mutex]’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/stl_construct.h:164:22,
    inlined from ‘static constexpr void std::allocator_traits<std::allocator<void> >::destroy(allocator_type&, _Up*) [with _Up = std::mutex]’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/alloc_traits.h:859:17,
    inlined from ‘void std::_Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp>::_M_dispose() [with _Tp = std::mutex; _Alloc = std::allocator<void>; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/shared_ptr_base.h:682:35,
    inlined from ‘void std::_Sp_counted_base<_Lp>::_M_release() [with __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/shared_ptr_base.h:423:18,
    inlined from ‘void std::_Sp_counted_base<_Lp>::_M_release() [with __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/shared_ptr_base.h:392:5,
    inlined from ‘std::__shared_count<_Lp>::~__shared_count() [with __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/shared_ptr_base.h:1136:21,
    inlined from ‘std::__shared_ptr<_Tp, _Lp>::~__shared_ptr() [with _Tp = json::Value; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/shared_ptr_base.h:1610:7,
    inlined from ‘std::shared_ptr<json::Value>::~shared_ptr()’ at /nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/shared_ptr.h:175:11,
    inlined from ‘json::Value::Ref::~Ref()’ at /home/whispers/scratchpad/binaryen/src/support/json.h:63:10,
    inlined from ‘json::Value::Ref wasm::PrintBoundary::getTypes(wasm::Type, bool, size_t)’ at /home/whispers/scratchpad/binaryen/src/passes/PrintBoundary.cpp:129:39:
/nix/store/mcd6qn183lsac6dy6xqm1ijhldixvfq2-gcc-16.1.0/include/c++/16.1.0/bits/stl_construct.h:88:9: error: array subscript ‘std::mutex[0]’ is partly outside array bounds of ‘unsigned char [24]’ [[-Werror=array-bounds=](https://gcc.gnu.org/onlinedocs/gcc-16.1.0/gcc/Warning-Options.html#index-Warray-bounds)]
   88 |         __location->~_Tp();
      |         ^~~~~~~~~~

followed by many more near-identical errors that I've omitted. We've also been encountering this in Nixpkgs while working on upgrading to GCC 16, and there are some full logs available at https://hydra.nixos.org/build/339164126/log (though they are for an older version, binaryen 129).

I've confirmed that this is the only kind of error by setting -DCMAKE_CXX_FLAGS="-Wno-error=array-bounds" and verifying that binaryen successfully builds.

I don't necessarily think this is a binaryen bug. The fact that the location of these warnings is within the the STL seems extremely… wrong. This may be an instance of the GCC bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122197 (in particular, the message about mutex, as there seems to be no mutexes in the affected code paths in binaryen that could be triggering this: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122197#c16). However, I wanted to bring this up here in order to seek confirmation that this is indeed not a binaryen bug, and if so, potentially suggest that binaryen suppress this particular warning in the default build configuration.