Paul Eggert <eggert@cs.ucla.edu> writes:

> On 4/29/19 7:53 AM, Alex Gramiak wrote:
>> would it make sense to first check _all_ (or, at least the
>> commonly supported) warning flags simultaneously and then only check
>> them individually if there was an error?
>
> Sure. That would be a nice thing to add to Gnulib (which is the upstream
> source for this).

Evidently I don't know enough autoconf to be able to do this myself,
since I couldn't figure out how to implement the fallback behaviour.
I've included a diff below that implements multiple-checking (~29s to
~22s configure time for me), with a faulty loop in the else clause
commented out. Is this salvageable?