GIR caller-allocates out-params (char *outbuf, gunichar *result) require
the caller to allocate and size the buffer, unlike callee-allocates T**
out-params where the callee fills in the pointee. The out-param
marshalling declared a single Swift scalar and passed its address, which
is correct only for the callee-allocates shape; for caller-allocates, C
wrote buffer payload past the one-element slot (g_unichar_fully_decompose)
or the payload was reinterpreted as a pointer and dereferenced
(g_unichar_to_utf8, segfault). GIR carries no buffer-size field, so these
are now skipped rather than generated. The guard also reclassifies
time_val_from_iso8601/signal_query/type_query from plainRecord to the
accurate caller-allocates reason.
Brendan Szymanski
b61512c4eb