Bug#1086680: lapack FTCBFS: unsatisfiable gfortran+python3 dependencies

[Helmut Grohne]

Source: lapack
Version: 3.12.0-3
Tags: patch
User: debian-cross at lists.debian.org
Usertags: cross-satisfiability

lapack cannot be cross built from source, because its dependency on
gfortran is not satsifiable and its dependency on the host architecture
python3 fails to install. It turns out that python3 is only used for
testing, so we may simply annotate it <!nocheck>. The gfortran
dependency was an unsolved issue as it needs "toolchain dependency cross
translation", but this has been solved earlier this year and we can now
translate it to gfortran-for-host. Beware that gfortran-for-host does
not provide a "gfortran" binary and requires the consumer to always call
it architecture-qualified. This is what lapack already does by setting
FC, but the use of gfortran-for-host turns this setting into a
requirement. I hope this is ok. Also note that lapack will not actually
cross build until gcc bug #1086679 is solved. I'm attaching a patch for
your convenience.

Helmut
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diff --minimal -Nru lapack-3.12.0/debian/changelog lapack-3.12.0/debian/changelog
--- lapack-3.12.0/debian/changelog	2024-02-07 12:30:40.000000000 +0100
+++ lapack-3.12.0/debian/changelog	2024-11-01 23:16:19.000000000 +0100
@@ -1,3 +1,12 @@
+lapack (3.12.0-3.1) UNRELEASED; urgency=medium
+
+  * Non-maintainer upload.
+  * Fix FTCBFS: (Closes: #-1)
+    + Translate gfortran dependency to gfortran-for-host.
+    + Annotate test dependency python3 with the nocheck profile.
+
+ -- Helmut Grohne <helmut at subdivi.de>  Fri, 01 Nov 2024 23:16:19 +0100
+
 lapack (3.12.0-3) unstable; urgency=medium
 
   * Add Breaks of liblapacke against older liblapack.so.3 flavours.
diff --minimal -Nru lapack-3.12.0/debian/control lapack-3.12.0/debian/control
--- lapack-3.12.0/debian/control	2024-02-07 10:56:36.000000000 +0100
+++ lapack-3.12.0/debian/control	2024-11-01 23:16:19.000000000 +0100
@@ -6,8 +6,8 @@
 Priority: optional
 Build-Depends: debhelper-compat (= 13),
                dh-exec
-Build-Depends-Arch: gfortran,
-                    python3
+Build-Depends-Arch: gfortran-for-host,
+                    python3 <!nocheck>
 Build-Depends-Indep: doxygen,
                      graphviz,
                      rename