Best practice: call an internal postgresql function (e.g. raw_parser) from another C/Rust binary

Hello!

(PostgreSQL rocks)

I wonder what is the easiest way to extract and (ab)use the raw_parser
function out of postgresql codebase, as a library, so I can use it from my
own code in Rust.

My C is rusty (pun intended) so I tried this:

cd src/backend/parser
gcc -I../../include -fpic -c parser.c

so raw_parser is present (yey):

nm parser.o | grep raw_parser
0000000000000000 T _raw_parser

but I missed lots of other implementation files (doh) ^^

nm parser.o | grep U
U _ScanKeywordTokens
U _ScanKeywords
U _base_yyparse
U _cancel_scanner_errposition_callback
U _core_yylex
U _errcode
U _errfinish
U _errhint
U _errmsg
U _errmsg_internal
U _errstart
U _isxdigit
U _palloc
U _parser_init
U _pg_unicode_to_server
U _repalloc
U _scanner_errposition
U _scanner_finish
U _scanner_init
U _scanner_isspace
U _scanner_yyerror
U _setup_scanner_errposition_callback
U _strlen
U _truncate_identifier

I started to include them one by one but the task is tedious and I'm pretty
sure there is an easier way :)

So I did take a look at various makefile in contrib/ folder but I'm not
sure adapting them will do want I want, I do not want to make an extension
for postgresql but instead generate an .a library that I can access from
Rust through FFI.

Does anyone tried this before?

PS: If you are interested, here is the repository:
https://github.com/FGRibreau/poc-pgsql-parser