LibKF6Breeze Icons and KIconLoader

[Jonathan Riddell]

I neon me and David R tracked it down to some optimization probably
with the dh_dwz tool from Debian packaging tools, this is the "DWARF
optimization and duplicate removal tool" part of the toolchain.

And with the discussion here Christoph has yesterday replaced the use
of qt_add_big_resources() with qt_add_resources() which also makes the
problem go away.
https://invent.kde.org/frameworks/breeze-icons/-/commit/fa44b11bc2b36d5c3cfc5c3403ea75b2fff57253

So beware use of qt_add_big_resources() it seems to be fragile to optimising.

Jonathan