bug#55676: [PATCH] non-recursive Lisp reader

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Fri, 27 May 2022 15:33:35 +0200
> 
> You probably saw this one coming. It's a restructuring of the Lisp reader so 
> that it no longer uses recursion for reading nested data structures.
> 
> The primary motivation is eliminating the limitation of the C stack (and 
> potential overflow crash). As a happy side-effect, the change improves reader 
> performance by a few percent, exact amount depending on what is being read. 
> This translates into a small but measurable speed-up in loading packages (.el 
> and .elc), and in byte-compilation. The performance increase is both from 
> removal of recursion and closer attention to performance.

Thanks.  One minor nit: you seem to have customized indentation in C
source files in a way that is different from our conventions.  Please
reformat using our defaults (which use a mix of TABs and SPACEs).