Solaris definition of struct std::lconv

[Jonathan Wakely]

Hi Rainer,

I've been working on PR57585 and have added a new
--enable-clocale=ieee_1003.1-2008
configure option. That should work on Solaris 11.4 (e.g. cfarm216) but
some members of the struct std::lconv are missing.

In <iso/locale_iso.h> the definition of lconv has:

/*
* New in IEEE Std 1003.1-2001 for alignment with the ISO/IEC 9899:1999
* standard.  Namespace and binary compatibility dictate that visibility
* of these new members be limited.  Visibility is limited to a strictly
* conforming ANSI C environment (-Xc) or if _LCONV_C99 is defined.
*/
#if (defined(_STRICT_STDC) && defined(_STDC_C99)) || defined(_LCONV_C99)
       char int_p_cs_precedes;
       char int_p_sep_by_space;
       char int_n_cs_precedes;
       char int_n_sep_by_space;
       char int_p_sign_posn;
       char int_n_sign_posn;
#endif

This block is not enabled for C++, but it should be, because C++17
incorporates the C99 standard library. So the C99 members of lconv
should be present in C++17 too.

Do you know if this is a known issue?

I can work around it by defining _LCONV_C99 in the relevant .cc files,
but it shouldn't be needed.