_AS_DETECT_BETTER_SHELL speedup (was: Re: Proposed doc updates)

[Stepan Kasal]

Hello,

> >   { nonexistent; } 2>/dev/null
> > and do not output anything with it.  They do fork for the { },
> ... if the redirection is applied:
...
> > Most newer shells don't fork for the { }, so that gives us a speed
> > advantage when using { ...; } rather than ( ...).

This means that a slight speedup of _AS_DETECT_BETTER_SHELL is
possible; see the attaches patch.

(Maybe I have discovered something which you already had in mind...)

Paul, OK to commit the patch?

Have a nice day,
        Stepan

as_detect_better_shell.patch
Description: Text document