Error using 'synaser.pas' with FreePascal (Lazarus) - arduino

Question

I'm trying to read serial data from an Arduino to my Mac (10.12.6). I have downloaded the Synapse library for FreePascal (Lazarus v.2.0.8) from here but I run into an error...
The Arduino is programmed using the Arduino IDE and sends random numbers (between 0 and 255) as a string to the serial port. I am trying to read these strings using FreePascal so that I can plot the values.
Following instructions here I have downloaded and used the Synapse library in the following way:
1) Uncompress the library folder
2) In Lazarus goto 'Project' -> 'Project Inspector' -> 'Add Files from File System' -> select 'synaser.pas'.
3) Add the following code to the form button event:
procedure TForm1.Button1Click(Sender: TObject);
var
ser: TBlockSerial;
begin
ser := TBlockSerial.Create;
try
ser.Connect('my-com-port'); // write here Arduino COM port number (on linux it's something like '/dev/ttyUSB0')
Sleep(250);
ser.config(9600, 8, 'N', SB1, False, False);
ser.SendString('on'); // button 2 should have 'off' here
finally
ser.free;
end;
end;
4) Press run.
An error message appears in the synaser.pas file:
Error incompatible types: got "ShortInt" expected "Pointer"..
Here's the part of the synaser.pas file referred to:
{$IFNDEF MSWINDOWS}
procedure TBlockSerial.Purge;
begin
{$IFNDEF FPC}
SerialCheck(ioctl(FHandle, TCFLSH, TCIOFLUSH));
{$ELSE}
{$IFDEF DARWIN}
SerialCheck(fpioctl(FHandle, TCIOflush, TCIOFLUSH)); { <------ here*******}
{$ELSE}
SerialCheck(fpioctl(FHandle, TCFLSH, Pointer(PtrInt(TCIOFLUSH))));
{$ENDIF}
{$ENDIF}
FBuffer := '';
ExceptCheck;
end;
I am using a Mac and this error seems to be related to a windows system?

Answer 1

Thanks #tonypdmtr.
I had to change the 'synaser.pas' file in the following way to get it to work. Bit of a hack I feel:
Change line 1939 to the following:
SerialCheck(fpioctl(FHandle, TCIOflush, Pointer(PtrInt(TCIOFLUSH))));
Comment out lines 2201, 2202 and 2204 in the same. This sounds like a bad way of doing it but I got it to work.
Changing the button event to the following code allows me to read a single line of data from the Arduino with each button click:
procedure TForm1.Button1Click(Sender: TObject);
var
ser: TBlockSerial;
begin
ser := TBlockSerial.Create;
try
ser.Connect('/dev/cu.wchusbserial1420'); // write here Arduino COM port number (on linux it's something like '/dev/ttyUSB0')
Sleep(250);
ser.config(9600, 8, 'N', SB1, False, False);
Label1.Caption := ser.RecvString(100);
finally
ser.free;
end;
end;
I feel the library should just work without having to change it.