The error in the log is:
:info:build FAILED: src/CMakeFiles/inkscape_base.dir/object/uri.cpp.o
:info:build /usr/bin/clang++ -DHAVE_CONFIG_H -DMAGICKCORE_HDRI_ENABLE=0 -DMAGICKCORE_QUANTUM_DEPTH=16 -DWITH_CSSBLEND -DWITH_MESH -DWITH_SVG2 -Dinkscape_base_EXPORTS -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/build/src -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/inkscape-1.3_2023-07-21_0e150ed6c4/src -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/inkscape-1.3_2023-07-21_0e150ed6c4 -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/build/include -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/inkscape-1.3_2023-07-21_0e150ed6c4/src/3rdparty/adaptagrams -isystem /opt/local/include/pango-1.0 -isystem /opt/local/include/harfbuzz -isystem /opt/local/include/fribidi -isystem /opt/local/include/cairo -isystem /opt/local/include/pixman-1 -isystem /opt/local/include/freetype2 -isystem /opt/local/include/libpng16 -isystem /opt/local/include/libsoup-2.4 -isystem /opt/local/include/libxml2 -isystem /opt/local/include/glib-2.0 -isystem /opt/local/lib/glib-2.0/include -isystem /opt/local/include -isystem /opt/local/include/poppler -isystem /opt/local/include/libwpg-0.3 -isystem /opt/local/include/libwpd-0.10 -isystem /opt/local/include/librevenge-0.0 -isystem /opt/local/include/libvisio-0.1 -isystem /opt/local/include/libcdr-0.1 -isystem /opt/local/include/gtkmm-3.0 -isystem /opt/local/lib/gtkmm-3.0/include -isystem /opt/local/include/atkmm-1.6 -isystem /opt/local/include/gtk-3.0/unix-print -isystem /opt/local/include/gdkmm-3.0 -isystem /opt/local/lib/gdkmm-3.0/include -isystem /opt/local/include/giomm-2.4 -isystem /opt/local/lib/giomm-2.4/include -isystem /opt/local/include/pangomm-1.4 -isystem /opt/local/lib/pangomm-1.4/include -isystem /opt/local/include/glibmm-2.4 -isystem /opt/local/lib/glibmm-2.4/include -isystem /opt/local/include/cairomm-1.0 -isystem /opt/local/lib/cairomm-1.0/include -isystem /opt/local/include/sigc++-2.0 -isystem /opt/local/lib/sigc++-2.0/include -isystem /opt/local/include/gtk-3.0 -isystem /opt/local/include/at-spi2-atk/2.0 -isystem /opt/local/include/at-spi-2.0 -isystem /opt/local/include/dbus-1.0 -isystem /opt/local/lib/dbus-1.0/include -isystem /opt/local/include/atk-1.0 -isystem /opt/local/include/gio-unix-2.0 -isystem /opt/local/include/gdk-pixbuf-2.0 -isystem /opt/local/include/gspell-1 -isystem /opt/local/include/enchant-2 -isystem /opt/local/include/gtksourceview-4 -isystem /opt/local/libexec/boost/1.76/include -isystem /opt/local/include/ImageMagick-6 -isystem /opt/local/include/2geom-1.3.0 -pipe -I/opt/local/libexec/boost/1.76/include -Os -Wno-invalid-constexpr -Wno-error=unknown-warning-option -Wno-unknown-warning-option -DNDEBUG -I/opt/local/libexec/boost/1.76/include -I/opt/local/include -stdlib=libc++ -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX14.sdk -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -DGLIBMM_DISABLE_DEPRECATED -DGTKMM_DISABLE_DEPRECATED -DGDKMM_DISABLE_DEPRECATED -DGTK_DISABLE_DEPRECATED -DGDK_DISABLE_DEPRECATED -fstack-protector-strong -Werror=format -Werror=format-security -Werror=ignored-qualifiers -Werror=return-type -Wno-switch -Wmisleading-indentation -D_GNU_SOURCE -DSIGCXX_DISABLE_DEPRECATED -arch arm64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX14.sdk -mmacosx-version-min=14.0 -fPIC -fPIC -fdiagnostics-color -std=gnu++17 -MD -MT src/CMakeFiles/inkscape_base.dir/object/uri.cpp.o -MF src/CMakeFiles/inkscape_base.dir/object/uri.cpp.o.d -o src/CMakeFiles/inkscape_base.dir/object/uri.cpp.o -c /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/inkscape-1.3_2023-07-21_0e150ed6c4/src/object/uri.cpp
:info:build /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/inkscape-1.3_2023-07-21_0e150ed6c4/src/object/uri.cpp:86:9: error: use of undeclared identifier 'xmlFree'
:info:build xmlFree(full);
:info:build ^
:info:build /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/inkscape-1.3_2023-07-21_0e150ed6c4/src/object/uri.cpp:89:9: error: use of undeclared identifier 'xmlFree'
:info:build xmlFree(escaped);
:info:build ^
:info:build /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_graphics_inkscape/inkscape/work/inkscape-1.3_2023-07-21_0e150ed6c4/src/object/uri.cpp:292:9: error: use of undeclared identifier 'xmlFree'
:info:build xmlFree(saveuri);
:info:build ^
:info:build 3 errors generated.
libxml2 was just updated from 2.11.x to 2.12.x; inkscape 1.3 is incompatible with this new version.
Here is the one-line change that we need to add to the port to fix it:
https://gitlab.com/inkscape/inkscape/-/commit/694d8ae43d06efff21adebf377ce614d660b24cd
