[gdal-dev] Sort files in static library to make the build reproducible

[Even Rouault]

Hi Bas,

> [I'm sending this to the list because I'm unable to successfully create
> a ticket with description in Trac at the moment. As reported in #6520
> [0] adding a ticket description causes an internal server errors on
> submit, it looks like the spam filter cannot handle the content.]

You got -3 points of karma due to:
ExternalLinks (-3): Maximum number of external links per post exceeded

(so somewhat changing a bit the links so they are no longer valid URL might 
potentially work)

and then :
IPThrottle (-4): Maximum number of posts per hour for this IP exceeded

Unfortunately it doesn't seem there's a way to whitelist users...

I've classified your attempts as 'ham' so hopefully the filter will lean from 
that...

> 
> 
> As part of the effort to support Reproducible Builds [1] Alexis
> Bienvenüe submitted two patches in Debian Bug #824808 [2] to sort the
> object files in the static library: sort-files-1 [3] & sort-files-2 [4]
> 
> These patches resolve the random_order_in_static_libraries issue [5],
> which is illustrated by the diffoscope output [6].
> 
> The attached patch is modified version of the sort-files-2 patch doing
> do wildcard sorting in the `$(LIBGDAL)` target instead of a separate
> 
> `$(LIBGDAL).buildit` target. Alexis chose that approach because:
> > In some situations some of the target dependencies do not exist
> > before the "make target" call. When this arises, as $(wildcard) is
> > expanded before building the dependencies, it can miss some files…
> > I was not sure of the situation here, so I added a transitional
> > target to be safe.
> 
> I prefer the single line change in the attached patch, but you may want
> to consider the separate target as done in the sort-files-2 patch too.

I've not an authoritative opinion on makefile issues. Was just wondering if one 
or another one of the approach might cause issues to "odd" environements, like 
mingw. But I see that we already do the backticks in the gdal.pc target.

Even

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