https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125956
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Libstdc++ already has this workaround elsewhere, so we should do the same in
format.cc:
// This adaptor works around the signature problems of the second
// argument to iconv(): SUSv2 and others use 'const char**', but glibc 2.2
// uses 'char**', which matches the POSIX 1003.1-2001 standard.
// Using this adaptor, g++ will do the work for us.
template<typename _Tp>
inline size_t
__iconv_adaptor(size_t(*__func)(iconv_t, _Tp, size_t*, char**, size_t*),
iconv_t __cd, char** __inbuf, size_t* __inbytes,
char** __outbuf, size_t* __outbytes)
{ return __func(__cd, (_Tp)__inbuf, __inbytes, __outbuf, __outbytes); }
