Re: incorrect use of 'pure' attribute

Hi Sam,

Sam James wrote:
> A function being idempotent / having 'call_once'
> semantics unfortunately doesn't make it suitable for the const
> attribute. This recently came up in both Mesa [0] and glib [1]
> and was confirmed by the GCC developers [2].
> 
> [0] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/42361
> [1] https://gitlab.gnome.org/GNOME/glib/-/work_items/3984
> [2] https://gcc.gnu.org/PR125916

Rather than have to manually review whole packages for this kind of
mistake, I think it would be good to have compiler warnings about these
incorrect uses of the 'const' and 'pure' attributes. Therefore I've
registered two issues for gcc and clang, respectively:

const:
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126757
  https://github.com/llvm/llvm-project/issues/215105

pure:
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126758
  https://github.com/llvm/llvm-project/issues/215106

Bruno