Bug#983099: perl FTCBFS: cross configs outdated

[Niko Tyni]

On Fri, Feb 19, 2021 at 09:22:32PM +0000, Dominic Hargreaves wrote:
> On Fri, Feb 19, 2021 at 11:00:20AM +0100, Helmut Grohne wrote:
> > Source: perl
> > Version: 5.32.1-2
> > Severity: important
> > X-Debbugs-Cc: debian-release at lists.debian.org
> > User: debian-cross at lists.debian.org
> > Usertags: ftcbfs
> > 
> > perl currently fails to cross build from source, due to a minor version
> > bump. Whenever the version is updated, the cross compilation configs
> > need to be updated and this didn't happen for perl.
 
> Niko, I see there is a debian/cross/extract-config-sh - could you
> possibly add a note to debian/README.source explaining the
> circumstances under which it needs to be run? I see there were multiple
> updates for 5.32.0 so it looks like it's not only with new upstream
> versions it needs to be run.

Sure. This is what I've just pushed in the ntyni/bug-983099 branch:

+Cross build support
+-------------------
+
+The build system currently support cross builds by storing architecture
+specific configuration information under the debian/cross/ directory in
+the source package. This works around for the lack of cross configuration
+support in the Configure script.
+
+These cross build support files need to be refreshed for new
+upstream versions, and whenever configuration options change. See
+debian/cross/README for more information.

along with some tooling examples in debian/cross/README.

The update in 5.32.0-6 was not strictly necessary. I probably did
it because I was looking at this stuff for #972559. It does not
hurt to update these files more often.

Incidentally, the fix for #972559 should reduce the churn in the support
files in the future a bit because build directory variations are now
masked. It doesn't help us quite yet, so the diffstat for updating them
for 5.32.1 (pushed to the same branch) is still quite daunting:

 60 files changed, 1000 insertions(+), 1000 deletions(-)

These changes have no run time effect, and they are only used for cross
building. I'll ask the release team next if this can still make it
to bullseye.

-- 
Niko