(I think this may be the usual LD_LIBRARY_PATH vs meson vs mac issue.)
FAILED: tests/GIMarshallingTests-1.0.typelib
/n0/gdt/NetBSD-current/pkgsrc/devel/gobject-introspection/work/gobject-introspection-1.64.0/output/tools/g-ir-compiler -o tests/GIMarshallingTests-1.0.typelib tests/GIMarshallingTests-1.0.gir --includedir /n0/gdt/NetBSD-current/pkgsrc/devel/gobject-introspection/work/gobject-introspection-1.64.0/output/gir --includedir /n0/gdt/NetBSD-current/pkgsrc/devel/gobject-introspection/work/gobject-introspection-1.64.0/output/tests
dyld: Library not loaded: @rpath/libgirepository-1.0.1.dylib
Referenced from: /n0/gdt/NetBSD-current/pkgsrc/devel/gobject-introspection/work/gobject-introspection-1.64.0/output/tools/g-ir-compiler
Reason: image not found
ninja: build stopped: subcommand failed.
*** Error code 1