Bug#798626: perl: -V lies about -Duseshrplib

[Niko Tyni]

On Sat, Jun 06, 2020 at 09:19:37PM -0400, Tom Lane wrote:
 
> I'd just like it to be on the record that this change broke the build
> process for PostgreSQL.
> 
> The immediate symptom is that "perl -V:useshrplib" no longer reports
> true, which causes our configure script to spit up, figuring that it is
> not going to be able to find a shared-library libperl to link against.
> We have determined after some experimentation that if we drop that
> safety check then we will still get a valid build on Debian, but it's
> fairly nervous-making that we will no longer be able to have that
> sanity check for other platforms.  Also, from what I understand of
> what you changed, it seems like there is a nontrivial risk that
> "perl -MExtUtils::Embed -e ldopts" would report linker flags that
> lead to linking in a static version of libperl.  That is likely
> to fail outright on some hardware (depending on how the static
> library was built); and if it doesn't fail, it will result in
> libperl.a becoming embedded in the calling package, which I surely
> hope is against your distribution policies.

Thanks for the note and the early testing!

I can see that "perl -V:useshrplib" is probably the best/only thing that
can be used to check whether a shared libperl is available, so it makes
sense for consumers to check that.

I'll reinstate the previous behaviour even though it's technically a lie.
-- 
Niko Tyni   ntyni at debian.org