- update to new upstream release 2.11
* New features:
- Add `json_pack()` format specifiers s*, o* and O* for values
that can be omitted if null (#339).
- Add `json_error_code()` to retrieve numeric error codes
(#365, #380, #381).
- Enable thread safety for `json_dump()` on all systems.
Enable thread safe `json_decref()` and `json_incref()` for
modern compilers (#389).
- Add `json_sprintf()` and `json_vsprintf()` (#393).
* Bug Fixes:
- Fix incorrect report of success from `json_dump_file()` when
an error is returned by `fclose()` (#359).
- Make json_equal() const-correct (#344).
- Fix incomplete stealing of references by `json_pack()` (#374)
- changelog from 2.9
* New features:
- Add JSON_EMBED encoding flag allowing arrays and objects to
be encoded into existing streams (#329).
- Add `json_dumpb()` function for dumping to a pre-allocated
buffer (#328).
- Add `json_dumpfd()` and `json_loadfd()` functions for dumping
to streaming file descriptors (#328).
- Add support for parsing buffers larger than 2GB (#309).