branches: 1.4.4;
Hide the private symbols.

Remove the now static _prop_format_default and _prop_string_type_tags.
Ride the minor bump from a few hours ago.
XXX should use -fvisibility=hidden and only export public symbols
XXX and then bump major

Add support for serializing to, and de-serializing from, JSON, as
specified in RFC 8259. Format is automatically detected for input,
and can be specified explicitly for output. The default format remains
XML.

As part of this change, generic prop_object_{internalize,externalize}()
functions are provided, and the "_with_format" flavor allows the output
format to be specified. Previous array- and dictionary-specific routines
remain for backwards compatibility.

libprop: Add expected symbols list.

NOTE: This exports a lot of _prop_* symbols which look internal and
aren't mentioned in any prop/*.h file. Intentional?

PR lib/58838: shared libraries in base should all have expsym lists