Misc/NEWS.d/next/Build/2021-10-12-02-13-08.bpo-45440.-zYgDb.rst

Building Python now requires a C99 ``<math.h>`` header file providing
the following functions: ``copysign()``, ``hypot()``, ``isfinite()``,
``isinf()``, ``isnan()``, ``round()``.
Patch by Victor Stinner.