Bug#1119324: c++ symbols renamed on ppc64el, need some guidance on this

Hello,

I think this bug needs deeper investigation. This FTBFS seems to be
specifically related to the ppc64el IEEE 128-bit float migration[1][2].

So far, as far as I can tell, it looks like the following symbols have
gone missing (replaced by the __ieee128 ones) as a result of the
migration, which probably results in an ABI break, potentially
necessitating a rename of the libzen0v5 binary package.

Original (from libzen0v5_0.4.41-2_ppc64el.deb):
0000000000016550 T _ZN6ZenLib6int128C1ERKg
0000000000016550 T _ZN6ZenLib6int128C2ERKg
0000000000027700 T _ZN6ZenLib6Ztring11From_NumberEghNS_8ztring_tE
0000000000017a90 T _ZN6ZenLib7uint128C1ERKg
0000000000017a90 T _ZN6ZenLib7uint128C2ERKg

New (from the FTBFS dpkg-gensymbols error):
_ZN6ZenLib6Ztring11From_NumberEu9__ieee128hNS_8ztring_tE@Base
_ZN6ZenLib6int128C1ERKu9__ieee128@Base
_ZN6ZenLib6int128C2ERKu9__ieee128@Base
_ZN6ZenLib7uint128C1ERKu9__ieee128@Base
_ZN6ZenLib7uint128C2ERKu9__ieee128@Base

The new symbols aren't a problem, but the old symbols being missing pose
a problem because IIUC, applications linked against libzen0v5 with the
old symbols will break until recompiled against the new lib (and they'll
break on user machines if the library package is upgraded but the
application isn't).

I haven't had time to build this on a porter box to see if the old
symbols have really gone missing, but since the correspondinng
(c++|regex) symbols are reported by dpkg-gensymbols as missing, I'm
assuming they are.

What confuses me, however is that there doesn't seem to be any
precedence for adding a name suffix to the lib package for any other
package. Is it not necessary? I could use some help understanding this.

[1] https://wiki.debian.org/ToolChain/IEEELongDouble
[2] https://lists.debian.org/debian-powerpc/2025/09/msg00046.html

P.S. I'm not subscribed to debian-powerpc, please cc me in replies.

-- 
Kind regards,
Loong Jin

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