link libraries are not quite right, on MacOS
Although the library path to the gtk3 libraries is being found by cmake during configure, it isn't being used in the final link and the link therefore fails. I had to add it manually like this:
LDFLAGS="-L /path/to/libdir" cmake ../
and then the link would finish.
A number of libraries are specified twice, for some reason, and that generates this warning:
[100%] Linking CXX executable pan/gui/pan
/opt/local/bin/cmake -E cmake_link_script CMakeFiles/pan.dir/link.txt --verbose=1
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++ -std=c++11 -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.2.sdk -Wl,-search_paths_first -Wl,-headerpad_max_install_names -L /opt/local/lib CMakeFiles/pan.dir/pan/gui/pan.cc.o CMakeFiles/pan.dir/pan/gui/gui.cc.o -o pan/gui/pan pan/gui/libpan-cc-gui.a pan/gui/libpan-c-gui.a pan/data-impl/libdata-impl.a pan/tasks/libtasks.a pan/data/libdata.a pan/usenet-utils/libusenet-utils.a pan/general/libgeneralutils.a uulib/libuulib.a -lgtk-3 -lgdk-3 -lpangocairo-1.0 -lpango-1.0 -lharfbuzz -latk-1.0 -lcairo-gobject -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lintl /opt/local/lib/libiconv.dylib /opt/local/lib/libz.dylib -lgmime-3.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lintl -lglib-2.0 -lintl -lgtkspell3-3 -lgtk-3 -lgdk-3 -lpangocairo-1.0 -lpango-1.0 -lharfbuzz -latk-1.0 -lcairo-gobject -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lintl -lenchant-2 -lenchant-2 /opt/local/lib/libiconv.dylib /opt/local/lib/libz.dylib -lgmime-3.0 -lgtkspell3-3 -lenchant-2
ld: warning: ignoring duplicate libraries: '-latk-1.0', '-lcairo', '-lcairo-gobject', '-lenchant-2', '-lgdk-3', '-lgdk_pixbuf-2.0', '-lgio-2.0', '-lglib-2.0', '-lgmime-3.0', '-lgobject-2.0', '-lgtk-3', '-lgtkspell3-3', '-lharfbuzz', '-lintl', '-lpango-1.0', '-lpangocairo-1.0'
[100%] Built target pan
/opt/local/bin/cmake -E cmake_progress_start /Users/Shared/source/pan/build/CMakeFiles 0
but in the end, it does link and work!