Compiler error after upgrade to macOS Catalina

Development Tools IDE 1.x
1

Compiling my sketches with macOS Mojave (10.14.6) and Arduino 1.8.11 (and all versions before) compiles without error.

After upgrading to macOS Catalina (10.15.3) all sketches using Arduino Uno ends with:

HardwareSerial0.cpp.o (symbol from plugin): In function Serial': (.text+0x0): multiple definition of __vector_18'
sketch/eg-ug.ino.cpp.o (symbol from plugin):(.text+0x0): first defined here
collect2: error: ld returned 1 exit status
exit status 1

The problem seems to be my own serial routine using ISR (USART_RX_vect) and ISR (USART_TX_vect)
These routines were originally developed with Microship Studio 4 and are uses to connect 12 atMega328p (Arduino like) via RS485 in an multiple Master / multiple Slave environment.
As they are working (until now) I didn't want to use the arduino Serial Library.

In all sketches I don't use any arduino SerialHardware Library, but the compiler seems to use it.
Any idee why and how I can solve the problem ?

2

It's the SerialEvent code that is breaking it, I think... were you previously using a significantly older version of the IDE? It was added a while ago, but not a really long time ago. Am surprised if it ever worked in a recent version of the ide

I wonder if adding your own main function to override the one in the core (which is weakly defined) would do the trick, by not calling the SerialEvent crap, which is garbage anyway, hence not pulling in any of the HardwareSerial stuff.

Eg

void main() {
setup();
while(1) loop();
}
3

Hello DrAzzy, thank for your reply.

On Mojave I used the latest 1.8.11 IDE, these HardwareSerial or SerialEvent problem occurs only after upgrading to Catalina (w/o any changes in the sketches or the Arduino.app).

Unfortunately using my own main() Funktion don't help.

How can I force the IDE not to use the Serial stuff ?