gdal +arrow needs to link to libatomic on 32-bit archs

[barracuda156]

[100%] Linking CXX shared module ../../../gdalplugins/ogr_Arrow.so
cd /opt/local/var/macports/build/_opt_PPCSnowLeopardPorts_gis_gdal/gdal/work/build/ogr/ogrsf_frmts/arrow && /opt/local/bin/cmake -E cmake_link_script CMakeFiles/ogr_Arrow.dir/link.txt --verbose=ON
/opt/local/bin/g++-mp-13 -pipe -DGDAL_COMPILATION -DNDEBUG -I/opt/local/include -I/opt/local/include/LegacySupport -I/opt/local/include/mpich-gcc13 -I/opt/local/include/mpich-gcc13 -D_GLIBCXX_USE_CXX11_ABI=0 -fvisibility=hidden -arch ppc -mmacosx-version-min=10.6 -bundle -Wl,-headerpad_max_install_names -L/opt/local/lib -Wl,-headerpad_max_install_names -lMacportsLegacySupport -o ../../../gdalplugins/ogr_Arrow.so CMakeFiles/ogr_Arrow.dir/ogrfeatherdriver.cpp.o CMakeFiles/ogr_Arrow.dir/ogrfeatherdataset.cpp.o CMakeFiles/ogr_Arrow.dir/ogrfeatherlayer.cpp.o CMakeFiles/ogr_Arrow.dir/ogrfeatherwriterdataset.cpp.o CMakeFiles/ogr_Arrow.dir/ogrfeatherwriterlayer.cpp.o  -Wl,-rpath,/opt/local/lib ../../../libgdal.35.3.9.0.dylib /opt/local/lib/libarrow.1601.0.0.dylib
Undefined symbols:
  "___atomic_load_8", referenced from:
      __ZNKSt13__atomic_baseIxEcvxEv in ogrfeatherlayer.cpp.o
ld: symbol(s) not found
collect2: error: ld returned 1 exit status
make[2]: *** [gdalplugins/ogr_Arrow.so] Error 1
make[2]: Leaving directory `/opt/local/var/macports/build/_opt_PPCSnowLeopardPorts_gis_gdal/gdal/work/build'
make[1]: *** [ogr/ogrsf_frmts/arrow/CMakeFiles/ogr_Arrow.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
[100%] Linking CXX shared module ../../../gdalplugins/ogr_Parquet.so
cd /opt/local/var/macports/build/_opt_PPCSnowLeopardPorts_gis_gdal/gdal/work/build/ogr/ogrsf_frmts/parquet && /opt/local/bin/cmake -E cmake_link_script CMakeFiles/ogr_Parquet.dir/link.txt --verbose=ON
/opt/local/bin/g++-mp-13 -pipe -DGDAL_COMPILATION -DNDEBUG -I/opt/local/include -I/opt/local/include/LegacySupport -I/opt/local/include/mpich-gcc13 -I/opt/local/include/mpich-gcc13 -D_GLIBCXX_USE_CXX11_ABI=0 -fvisibility=hidden -arch ppc -mmacosx-version-min=10.6 -bundle -Wl,-headerpad_max_install_names -L/opt/local/lib -Wl,-headerpad_max_install_names -lMacportsLegacySupport -o ../../../gdalplugins/ogr_Parquet.so CMakeFiles/ogr_Parquet.dir/ogrparquetdriver.cpp.o CMakeFiles/ogr_Parquet.dir/ogrparquetdataset.cpp.o CMakeFiles/ogr_Parquet.dir/ogrparquetlayer.cpp.o CMakeFiles/ogr_Parquet.dir/ogrparquetwriterdataset.cpp.o CMakeFiles/ogr_Parquet.dir/ogrparquetwriterlayer.cpp.o CMakeFiles/ogr_Parquet.dir/ogrparquetdatasetlayer.cpp.o  -Wl,-rpath,/opt/local/lib ../../../libgdal.35.3.9.0.dylib /opt/local/lib/libarrow_dataset.1601.0.0.dylib /opt/local/lib/libparquet.1601.0.0.dylib /opt/local/lib/libarrow_acero.1601.0.0.dylib /opt/local/lib/libarrow.1601.0.0.dylib
Undefined symbols:
  "___atomic_load_8", referenced from:
      __ZNKSt13__atomic_baseIxEcvxEv in ogrparquetdriver.cpp.o
      __ZNKSt13__atomic_baseIxEcvxEv in ogrparquetdataset.cpp.o
      __ZNKSt13__atomic_baseIxEcvxEv in ogrparquetlayer.cpp.o
      __ZNKSt13__atomic_baseIxEcvxEv in ogrparquetdatasetlayer.cpp.o
ld: symbol(s) not found
collect2: error: ld returned 1 exit status
make[2]: *** [gdalplugins/ogr_Parquet.so] Error 1
make[2]: Leaving directory `/opt/local/var/macports/build/_opt_PPCSnowLeopardPorts_gis_gdal/gdal/work/build'
make[1]: *** [ogr/ogrsf_frmts/parquet/CMakeFiles/ogr_Parquet.dir/all] Error 2
make[1]: Leaving directory `/opt/local/var/macports/build/_opt_PPCSnowLeopardPorts_gis_gdal/gdal/work/build'
make: *** [all] Error 2

[barracuda156]

In 5cae48510969443fdccb65c53e39acb6906de625/macports-ports (master):

gdal: fix arrow variant on 32-bit platforms

Closes: #70298