[Bug libgcc/96845] New: undefined reference to `__aarch64_ldadd4_acq_rel'

[bero at lindev dot ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96845

            Bug ID: 96845
           Summary: undefined reference to `__aarch64_ldadd4_acq_rel'
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgcc
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bero at lindev dot ch
  Target Milestone: ---

When compiling some packages on aarch64 (e.g. polkit-qt-1 0.113.0) on aarch64,
the build errors out with

/usr/lib64/gcc/aarch64-openmandriva-linux-gnu/10.2.0/../../../../aarch64-openmandriva-linux-gnu/bin/ld:
core/CMakeFiles/polkit-qt5-core-1.dir/polkitqt1-authority.cpp.o: in function
`std::__atomic_base<int>::operator++()':
/usr/include/c++/10.2.0/bits/atomic_base.h:326: undefined reference to
`__aarch64_ldadd4_acq_rel'

This seems to be caused by __aarch64_ldadd4_acq_rel being defined in libgcc,
but not libgcc_s, while only libgcc_s is pulled in automatically.

Some Linux distributions have a workaround for this in their gcc packaging -
they replace libgcc_s.so with an ld script that pulls in libgcc if needed (see
e.g. https://src.fedoraproject.org/rpms/gcc/blob/master/f/gcc.spec#_1303 )