Re: About ./configure --cache-file (WAS: CHECK_STRUCTS/dmpstruct.h mechanism is broken.)

[Eli Zaretskii]

> Date: Sun, 14 Apr 2019 09:45:35 +0000
> Cc: Noam Postavsky <address@hidden>, Eli Zaretskii <address@hidden>,
>   Emacs developers <address@hidden>
> From: Alan Mackenzie <address@hidden>
> 
> > ... or if you configure with different flags, or if you edit
> > configure.ac or if you do a bunch of other things. For the kind of
> > work I do, the cache is way more trouble than it's worth.
> 
> Are you sure?  I just tried it out.  My first run,
>     ./configure -C --with-gif=no --with-tiff=no --with-gpm=no
> , took ~2.3 seconds.  I built Emacs, and GPM was indeed not built in.
> 
> Then I did
>     ./configure -C --with-gif=no --with-tiff=no --with-gpm
> , which again took ~2.3s, built Emacs, and GPM was then present and
> working.

I think you should try building with --with-gpm=no, and after than
without this switch, i.e. without an explicit --with-gpm.

> So it seems that ./configure -C can cope with at least some flags being
> changed between runs.

I think you are just being lucky: configure always recomputes
variables that are not cached yet.