>>>>> Dirk Eddelbuettel writes: > Hi Helmut,
> I will CC Kurt Hornik from the upstream team for R, he is the principal > author of the extensive autoconf etc pieces for R. > On 30 March 2026 at 18:27, Helmut Grohne wrote: > | Source: r-base > | Version: 4.5.3-1 > | Tags: patch > | User: [email protected] > | Usertags: cross-satisfiability ftcbfs > | > | r-base fails to cross build from source for a pile of reasons. > | > | Initially, its Build-Depends cannot be satisfied. This is due to "gcc", > | "g++" and "gfortran". For supporting cross compilation, toolchain > | dependencies need to be translated and declare what architecture they > | are being used for. In case of gcc and g++, both the build and host > | architecture toolchain is implied in build-essential. The version > | constraint is satisfied in oldoldstable. I suggest dropping them. > Yes. I recall us having email about this before but for some reason it stuck. > R is in pre-release for R 4.6.0 so I can easily try a few builds (up until > the release on April 24). > | gfortran is used to compile Fortran code for the host architecture. > | Hence, it should be suffixed -for-host. Once doing so, you may no longer > | assume presence of unprefixed tools such as "gfortran". Instead, > | ${DEB_HOST_GNU_TYPE}-gfortran must be used. This leads to the second > | problem. > | > | Use of bare tools. debian/rules uses bare tool names such as gcc, g++ > | and gfortran in several places. Those compile for the build > It's an old file, and some/most of the shenanigans were/are needed ... > | architecture, but the package is supposed to be built for the host > | architecture. Those tools all need to be prefixed with a host > | architecture triplet. Fortunately, dpkg has a buildtools.mk file that > | can be included to supply all those tools. > | > | In the attached patch, I opt for replacing the variable names for tools > | with those used by buildtools.mk. For instance, compiler becomes CC and > | cxxcompiler becomes CXX. This also happens to match what the upstream > | build system expects. > I appreciate this and will fold it in. > | Last but not least, for cross building an autotools project one needs to > | pass --build and --host to configure. Since the package does not use > | dh_auto_configure, this must be done explicitly. > | > | You can find all of the necessary changes in the attached patch. Once > | applying it, r-base will not cross build. The upstream build system uses > | a pile of AC_RUN_IFELSE checks and any of them makes a cross build fail. > Kurt, this is your corner. 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? -k > | most of them are cached, so a cross builder may supply a result via the > | environment. Going from there to a full cross build is another piece, > | but the attached patch at least makes Build-Depends satisfiable and > | proceeds to the configure step. > Following April 24, R gets into a new annual cycle. With your assistance, > maybe upstream (and the Debian package) can (finally) to cross-build and > repeated builds. > Dirk > | Helmut > | x[DELETED ATTACHMENT r-base_4.5.3-1.1.debdiff, plain text] > -- > dirk.eddelbuettel.com | @eddelbuettel | [email protected]
