Re: build 2 similar binary packages from one source tree

[Adam Borowski <kilobyte@angband.pl>]

On Mon, Dec 25, 2017 at 01:43:13AM +0900, Osamu Aoki wrote:
> maildrop source tree can be build with different build option to produce
> maildrop program in 2 ways for each arch.
> 
>  * set GID mail without restricted caller (maildrop)
>  * set UID root with restricted caller for courier-mta
>    (maildrop-courier) -- This is now missing in archive but we used to
>    have it.
> 
> Of course we can build 2 source packages to do this.  But is there any
> easy clean way to do this without making 2 source packages with
> identical upstream tarball.
> 
> Any pointer to a simple example which uses autotools as its build script
> is appreciated.  (Program example simpler than glibc or linux kernel is
> appreciated.)

While autotools in principle do support out-of-tree builds, a particular
program might still fail.  And, most non-autotools non-cmake build systems
don't support that at all.

In such cases, there's a heavy hammer of linking the whole build tree to
two temporary directories, and building from those.

For example, crawl does:

tree-stamp:
        dh_testdir
        mkdir build-console
        cp -ldpR docs settings source CREDITS.txt build-console/
        mkdir build-tiles
        cp -ldpR docs settings source CREDITS.txt build-tiles/
        touch tree-stamp

then for actual build:
        cd build-console/source && $(MAKE) $(ARGS_CONSOLE)
        cd build-tiles/source && $(MAKE) $(ARGS_TILES)


Meow!
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