Re: [Emacs-diffs] trunk r117846: Add macros to allocate temporary Lisp objects with alloca.

[Paul Eggert]

Dmitry Antipov wrote:
> No ideas why alignas (X) is designed in such a way.

You'll have to ask the committee. :-)  For C11, the C standardization 
committee decided to allow alignas only when declaring objects; alignas 
cannot be used in typedefs or in the definitions of structures.  Emacs 
prefers alignas when it works, since alignas is standardized and is more 
likely to be portable, but for this particular feature (an aligned 
structure type) Emacs uses a GCC extension instead, since there's no way 
to do it in the standard.

I'll try to review the code carefully soon.