[Bug libfortran/104233] [12 regression] ieee/issignaling_fallback.h broke Solaris/SPARC bootstrap

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104233

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think testing __FLT128_IS_IEC_60559__ next to it is fine too, if __float128
and _Float128 exists, they are on all supported targets the same IEEE quad
types, just _Generic doesn't treat them as the same type.