[clang][headers] Need a way for math.h to share the definitions of INIFINITY and NAN with float.h (#164348)
In C23 mode, both float.h and math.h are required to define INIFINITY
and NAN. However, with clang modules, there needs to be a single owner
for the declarations. Let that be float.h since that's the suggested
true owner in Annex F.2.2 of ISO/IEC 9899:2024, and introduce
`__need_infinity_nan` so that math.h can pick up the compiler
definitions.
GitOrigin-RevId: 38473c5d351d6b2ae21b5eb1ce66c2bcc2f7c6f7
2 files changed
