3.0b1 build error with musl c library

[Chocimier]

Tested to build 3.0b1 for Void Linux. With glibc it compiles, but not with musl:

/builddir/fish-3.0b1/src/builtin_printf.cpp: In function 'T raw_string_to_scalar_type(const wchar_t*, wchar_t**) [with T = long double]':
/builddir/fish-3.0b1/src/builtin_printf.cpp:278:12: error: 'wcstod_l' was not declared in this scope
     return wcstod_l(s, end, fish_c_locale());
            ^~~~~~~~
/builddir/fish-3.0b1/src/builtin_printf.cpp:278:12: note: suggested alternative: 'wcstoull'
     return wcstod_l(s, end, fish_c_locale());
            ^~~~~~~~
            wcstoull

/builddir/fish-3.0b1/src/wutil.cpp: In function 'double fish_wcstod(const wchar_t*, wchar_t**)':
/builddir/fish-3.0b1/src/wutil.cpp:776:12: error: 'wcstod_l' was not declared in this scope
     return wcstod_l(str, endptr, fish_c_locale());
            ^~~~~~~~
/builddir/fish-3.0b1/src/wutil.cpp:776:12: note: suggested alternative: 'wcstoull'
     return wcstod_l(str, endptr, fish_c_locale());
            ^~~~~~~~
            wcstoull

[faho]

I just added ffab420, which adds the stupidest possible wcstod_l "implementation".

It builds and runs on void musl.

[andrew-schulman]

FYI, Cygwin also has this problem. ffab420 seems to fix it.