Linking issue on a mac for Blinky project

[ibitbang]

I get the error below when compiling the sketch on macos High Sierra, with Arduino 1.8.4 and teensyduino on top.

My Sketch

/*
 * Example to demonstrate thread definition, semaphores, and thread sleep.
 */


// The LED is attached to pin 13 on Arduino.
const uint8_t LED_PIN = 13;

// Declare a semaphore handle.
SemaphoreHandle_t sem;
//------------------------------------------------------------------------------
/*
 * Thread 1, turn the LED off when signalled by thread 2.
 */
// Declare the thread function for thread 1.
static void Thread1(void* arg) {
  while (1) {

    // Wait for signal from thread 2.
    xSemaphoreTake(sem, portMAX_DELAY);

    // Turn LED off.
    digitalWrite(LED_PIN, LOW);
  }
}
//------------------------------------------------------------------------------
/*
 * Thread 2, turn the LED on and signal thread 1 to turn the LED off.
 */
// Declare the thread function for thread 2.
static void Thread2(void* arg) {

  pinMode(LED_PIN, OUTPUT);

  while (1) {
    // Turn LED on.
    digitalWrite(LED_PIN, HIGH);

    // Sleep for 200 milliseconds.
    vTaskDelay((200L * configTICK_RATE_HZ) / 1000L);

    // Signal thread 1 to turn LED off.
    xSemaphoreGive(sem);

    // Sleep for 200 milliseconds.
    vTaskDelay((200L * configTICK_RATE_HZ) / 1000L);
  }
}
//------------------------------------------------------------------------------
void setup() {
  portBASE_TYPE s1, s2;

  Serial.begin(9600);
  
  // initialize semaphore
  sem = xSemaphoreCreateCounting(1, 0);

  // create task at priority two
  s1 = xTaskCreate(Thread1, NULL, configMINIMAL_STACK_SIZE, NULL, 2, NULL);

  // create task at priority one
  s2 = xTaskCreate(Thread2, NULL, configMINIMAL_STACK_SIZE, NULL, 1, NULL);

  // check for creation errors
  if (sem== NULL || s1 != pdPASS || s2 != pdPASS ) {
    Serial.println(F("Creation problem"));
    while(1);
  }
  // start scheduler
  vTaskStartScheduler();
  Serial.println(F("Insufficient RAM"));
  while(1);
}
//------------------------------------------------------------------------------
// WARNING idle loop has a very small stack (configMINIMAL_STACK_SIZE)
// loop must never block
void loop() {
  // Not used.
}

Error log

Linking everything together...
"/Applications/Arduino.app/Contents/Java/hardware/teensy/../tools/arm/bin/arm-none-eabi-gcc" -O2 -Wl,--gc-sections,--relax,--defsym=__rtc_localtime=1506482470 "-T/Applications/Arduino.app/Contents/Java/hardware/teensy/avr/cores/teensy3/mk20dx256.ld" -lstdc++  -mthumb -mcpu=cortex-m4 -fsingle-precision-constant -o "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/freertos.ino.elf" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/sketch/freertos.ino.cpp.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/FreeRTOS_ARM.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/assertMsg.cpp.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/basic_io_arm.cpp.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/croutine.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/event_groups.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/heap_3.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/list.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/port.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/queue.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/tasks.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/timers.c.o" "/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/core/core.a" "-L/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264" -larm_cortexM4l_math -lm
/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/core/core.a(EventResponder.cpp.o): In function `pendablesrvreq_isr':
/Applications/Arduino.app/Contents/Java/hardware/teensy/avr/cores/teensy3/EventResponder.cpp:86: multiple definition of `pendablesrvreq_isr'
/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/port.c.o:/Users/xxxxxxxxx/Documents/Arduino/libraries/FreeRTOS_ARM/src/utility/port.c:469: first defined here
/Applications/Arduino.app/Contents/Java/hardware/tools/arm/bin/../lib/gcc/arm-none-eabi/5.4.1/../../../../arm-none-eabi/bin/ld: Disabling relaxation: it will not work with multiple definitions
/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/core/core.a(EventResponder.cpp.o): In function `EventResponder::triggerEventNotImmediate()':
/Applications/Arduino.app/Contents/Java/hardware/teensy/avr/cores/teensy3/EventResponder.cpp:45: multiple definition of `systick_isr'
/var/folders/0p/861x6w911d32vmxzcgxm8wpm0000gn/T/arduino_build_335264/libraries/FreeRTOS_ARM/utility/port.c.o:/Users/xxxxxxxxx/Documents/Arduino/libraries/FreeRTOS_ARM/src/utility/port.c:291: first defined here
collect2: error: ld returned 1 exit status
Using library FreeRTOS_ARM at version 2015.11.12 in folder: /Users/xxxxxxxxx/Documents/Arduino/libraries/FreeRTOS_ARM 

[greiman]

Looks like the new Teensy EventResponder is causing the problem. I have decided it is not worth supporting FreeRTOS on Arduino.

See this.