Add libpg_query (sql parser library) (fffaraz#1552)

Author: toge

README.md

@@ -418,6 +418,7 @@ A curated list of awesome C++ (or C) frameworks, libraries, resources, and shiny
 * [Infinity](https://github.com/infiniflow/infinity) - The AI-native database built for LLM applications, providing incredibly fast vector and full-text search. [Apache2]
 * [Kvrocks](https://github.com/apache/incubator-kvrocks) - A distributed key value NoSQL database that uses RocksDB as storage engine and is compatible with Redis protocol. [Apache2]
 * [LevelDB](https://github.com/google/leveldb) - A fast key-value storage library written at Google that provides an ordered mapping from string keys to string values. [BSD]
+* [libpg_query](https://github.com/pganalyze/libpg_query) - C library for accessing the PostgreSQL parser outside of the server environment. [BSD-3-Clause]
 * [libpqxx](https://github.com/jtv/libpqxx) - The official C++ client API for PostgreSQL. [BSD-3-Clause]
 * [LMDB](https://www.symas.com/lmdb) - Very fast embedded key/value store with full ACID semantics. [OpenLDAP]
 * [LMDB++](https://github.com/bendiken/lmdbxx) - C++11 wrapper for the LMDB embedded database library. [PublicDomain]