Test PostgreSQL 12 compatibility about plswift HOT 3 OPEN

public extension FunctionCallInfoBaseData {
  
  /// Access PostgreSQL function call arguments as a Datum
  subscript(datum idx: Int) -> Datum? {
    // convert tuple to index
    switch idx {
      case 0: return args.0
      case 1: return args.1
      case 2: return args.2
      case 3: return args.3
      case 4: return args.4
      case 5: return args.5
      case 6: return args.6
      case 7: return args.7
      default: return nil
    }
  }
  
  /// Access PostgreSQL function call arguments as an Int
  subscript(int idx: Int) -> Int {
    guard let datum = self[datum: idx] else { return -42 }
    return datum.intValue
  }
}

typedef struct FunctionCallInfoData
{
	FmgrInfo   *flinfo;			/* ptr to lookup info used for this call */
	fmNodePtr	context;		/* pass info about context of call */
	fmNodePtr	resultinfo;		/* pass or return extra info about result */
	Oid			fncollation;	/* collation for function to use */
	bool		isnull;			/* function must set true if result is NULL */
	short		nargs;			/* # arguments actually passed */
	Datum		arg[FUNC_MAX_ARGS];		/* Arguments passed to function */
	bool		argnull[FUNC_MAX_ARGS]; /* T if arg[i] is actually NULL */
} FunctionCallInfoData;

typedef struct FunctionCallInfoBaseData
{
        FmgrInfo   *flinfo;                     /* ptr to lookup info used for this call */
        fmNodePtr       context;                /* pass info about context of call */
        fmNodePtr       resultinfo;             /* pass or return extra info about result */
        Oid                     fncollation;    /* collation for function to use */
#define FIELDNO_FUNCTIONCALLINFODATA_ISNULL 4
        bool            isnull;                 /* function must set true if result is NULL */
        short           nargs;                  /* # arguments actually passed */
#define FIELDNO_FUNCTIONCALLINFODATA_ARGS 6
        NullableDatum args[FLEXIBLE_ARRAY_MEMBER];
} FunctionCallInfoBaseData;

# swift pl build
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:17:22: error: cannot find 'args' in scope
      case 0: return args.0
                     ^~~~
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:18:22: error: cannot find 'args' in scope
      case 1: return args.1
                     ^~~~
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:19:22: error: cannot find 'args' in scope
      case 2: return args.2
                     ^~~~
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:20:22: error: cannot find 'args' in scope
      case 3: return args.3
                     ^~~~
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:21:22: error: cannot find 'args' in scope
      case 4: return args.4
                     ^~~~
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:22:22: error: cannot find 'args' in scope
      case 5: return args.5
                     ^~~~
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:23:22: error: cannot find 'args' in scope
      case 6: return args.6
                     ^~~~
/root/helloswiftpl/.build/checkouts/PLSwift/Sources/PLSwift/PGFunction.swift:24:22: error: cannot find 'args' in scope
      case 7: return args.7
                     ^~~~
[1/1] Compiling PLSwift PGFunction.swift