Log Message:
textproc/json-c: Update to 0.18

Changelog:
0.18 (up to commit 6bfab90, 2023-09-15)
========================================

Deprecated and removed features:
--------------------------------
* Clean up pre-3.9 CMake support in CMakeLists.txt

New features
------------
* Build pkg-config for msvc as well

Significant changes and bug fixes
---------------------------------
* Critical fix for binary compatibility with 0.16: Move the
  json_tokener_error_memory entry to the end of enum json_tokener_error.
* Issue #829: attempt to detect clang-cl.exe and pass MSVC-compatile command
  line arguments.
* PR #831 - rename WIN32 to _WIN32
* PR #839 - Fix gcc 5 "may be used uninitialized" failure in json_pointer.c
* PR #849 - random_seed.c: add a Coverity Scan suppression
* Issue #854: Set error=json_tokener_error_memory in
  json_tokener_parser_verbose() when allocating the tokener fails.
* Issue #857: fix a few places where json_tokener should have been returning
  json_tokener_error_memory but wasn't.
* Handle yet another out-of-memory condition in json_tokener, duplocate can
  return NULL.
* Various fixes in the fuzzers
* A few minor doc fixes