[base] `close` callback may not use stream->memory
The documentation for FT_StreamRec::memory
states that it "shouldn't
be touched by stream implementations". This true even for internal
implementations of the close
callback, since it is not guaranteed that
the memory
will even be set when the close
callback occurs.
- src/base/ftobjs.c (new_memory_stream): stash current
memory
instream->descriptor
. (memory_stream_close): use it