As of libc++19[1], std::char_traits<> is now only provided for char, char8_t, char16_t, char32_t, and wchar_t, and any instantiation for other types will fail. This breaks GNU APL on the FreeBSD package build cluster[2]. I've briefly glanced over the problematic code and it looks like it may need more than simply adjusting the template or enum types here or there. Perhaps it is time to adapt to the new standard before GCC stops accepting current code as well?
./danfe [1] https://libcxx.llvm.org/ReleaseNotes/19.html#deprecations-and-removals [2] https://pkg-status.freebsd.org/beefy18/data/main-amd64-default/p7c3dbec016b0_s054c5ddf587/logs/gnu-apl-1.8_3.log
