Hello Kurt and Dirk,
On Fri, Apr 10, 2026 at 10:32:50AM -0500, Dirk Eddelbuettel wrote:
> | Thanks. Not much I can do about this: R-admin has forever said
> |
> | The @file{configure} script has other generic options added by
> | @command{autoconf} and which are not supported for @R{}: in particular
> | building for one architecture on a different host is not possible.
> |
> | Is there a case for cross-building?
>
> It is my understanding that some Debian architectures use it but Helmut will
> know more and may chime in.
cross building is a general feature of the Debian archive and is
supported on a best-effort basis. At present this means that roughly
every other package happens to be cross buildable.
When I filed this bug, I asked for the inclusion of provided
improvements for cross building. Dirk applied them all. Thank you. I
noted that even with the changes, r-base would still not cross build due
to problems relating to configure. I did not mean to imply that you
should be working on those other problems.
You can see how the upload made r-base cross build testable:
https://crossqa.debian.net/src/r-base
> Either way, this should be addressable as Debian surely hits other upstream
> sources using autoconf so I have some hope that between all of us we may just
> be missing a small step to facilitate this.
The relevant pieces happen to be relatively unique to r-base. Most of
them relate to AC_RUN_IFELSE and you'll find quite a few of those in
m4/R.m4. It's not like R would b using AC_RUN_IFELSE without reason.
Most of those checks cannot be turned into AC_LINK_IFELSE or
AC_COMPILE_IFELSE without degrading them and most of them have cache
variables.
It is quite a number of checks. A cross builder could be scraping the
results and feed them into the build via the environment. I did not try
to see whether that suffices.
There is no immediate and pressing need to make R cross buildable from
my point of view. The way it was failing earlier was relatively
obviously buggy and I sent a patch for the low hanging fruit. Let's
leave the harder nuts for when there is a need.
Helmut
