Previously we had both e.g. GI_TYPE_TAG_LONG and GI_TYPE_TAG_INT64,
but in fact the typelib is already machine-specific, so it makes sense
to just encode this as a fixed type. The .gir remains abstract.
We also remove size_t from the typelib; one would never want to treat
it differently than an integer.
time_t is removed as well; while bindings like gjs had special handling
to turn it into e.g. a JS Date object, I don't think we should encourage
people to use these POSIX types in their API. Use GTimeVal or the like
instead.
Because the typelib is now really machine-specific, we need to remove
the -expected.tgirs from git. (We could potentially add a check
which wasn't just a literal diff later)
https://bugzilla.gnome.org/show_bug.cgi?id=623774