AppleClang compiler warning with C++17

[pablode]

Apparently codecvt_utf8 has been deprecated in C++17:

[ 82%] Building CXX object extern/openexr/src/lib/OpenEXR/CMakeFiles/OpenEXR.dir/ImfMisc.cpp.o
/Users/pablode/Work/gatling/extern/openexr/src/lib/OpenEXR/ImfMisc.cpp:1990:31: warning: 'codecvt_utf8<wchar_t>' is deprecated [-Wdeprecated-declarations]
    std::wstring_convert<std::codecvt_utf8<wchar_t>, wchar_t> converter;
                              ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/include/c++/v1/codecvt:187:28: note: 'codecvt_utf8<wchar_t>' has been explicitly marked deprecated here
class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 codecvt_utf8
                           ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/include/c++/v1/__config:1037:41: note: expanded from macro '_LIBCPP_DEPRECATED_IN_CXX17'
#    define _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_DEPRECATED
                                        ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/include/c++/v1/__config:1010:49: note: expanded from macro '_LIBCPP_DEPRECATED'
#      define _LIBCPP_DEPRECATED __attribute__((__deprecated__))
                                                ^
/Users/pablode/Work/gatling/extern/openexr/src/lib/OpenEXR/ImfMisc.cpp:1990:10: warning: 'wstring_convert<std::codecvt_utf8<wchar_t>>' is deprecated [-Wdeprecated-declarations]
    std::wstring_convert<std::codecvt_utf8<wchar_t>, wchar_t> converter;
         ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/include/c++/v1/locale:3598:28: note: 'wstring_convert<std::codecvt_utf8<wchar_t>>' has been explicitly marked deprecated here
class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 wstring_convert
                           ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/include/c++/v1/__config:1037:41: note: expanded from macro '_LIBCPP_DEPRECATED_IN_CXX17'
#    define _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_DEPRECATED
                                        ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/include/c++/v1/__config:1010:49: note: expanded from macro '_LIBCPP_DEPRECATED'
#      define _LIBCPP_DEPRECATED __attribute__((__deprecated__))
                                                ^
2 warnings generated.