wcstod, wcstof, wcstold, wcstol, wcstoll, wcstoul, wcstoull, wcscoll and wcsxfrm still forwarded to the host's wchar_t functions, which use 32-bit units on Linux. The wcsto* functions now parse the ASCII prefix of the guest string with the narrow parsers, as the C locale accepts only ASCII white space and digits. wcscoll compares like wcscmp and wcsxfrm copies, as strcoll and strxfrm do in the C locale.
The guest's wchar_t is 16 bits, but wcslen, wcscmp, wcsncmp, wcscpy, wcsncpy, wcschr, wcsrchr, wcsstr, wcspbrk, wcsspn and the wmem functions forwarded to the host's wchar_t functions, which use 32-bit units on Linux. Implement them on char16_t. The wide conversions that still use the host's wchar_t are listed in TechnicalDebt.
Fishybeing