[Bug libstdc++/115797] [15 Regression] 'extern "C" { #include <math.h> }' fails with 'error: template with C linkage' since r15-1857-gde19b516edbf91

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115797

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #1)
> Doing this is undefined (and annoying).

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=13071#c12

Is libstdc++ still allowing this for qoi? Or we going to change our policy and
just forgot about this crappy code? I vote to not to support this.