firmware: link error with avr gcc 5.4.0

[pat1]

We need to use gcc <> 5.4.0

avr-g++ -o .pio/build/1284p16m/src/stima.ino.cpp.o -c -std=gnu++11 -fno-exceptions -fno-threadsafe-statics -fpermissive -std=gnu++11 -Os -w -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -MMD -flto -include include/FreeRTOSConfig.h -fstack-usage -Wstack-usage=200 -Os -Wall -ffunction-sections -fdata-sections -flto -mmcu=atmega1284p -DPLATFORMIO=50100 -DARDUINO_AVR_MICRODUINO_CORE_PLUS -DARDUINO_ARCH_AVR -DCPP_FREERTOS_NO_CPP_STRINGS -DCPP_FREERTOS_NO_EXCEPTIONS -DATMEGA1284 -DportUSE_WDTO=WDTO_1S -DF_CPU=16000000L -DARDUINO_ARCH_AVR -DARDUINO=10808 -Isrc -I/home/pat1/git/rmap/arduino/sketchbook/libraries/FreeRTOS/src -I/home/pat1/git/rmap/arduino/sketchbook/libraries/MQTTClient -I/home/pat1/git/rmap/arduino/sketchbook/libraries/arduinoJsonRPC -I/home/pat1/git/rmap/arduino/sketchbook/libraries/SensorDriver -I/home/pat1/git/rmap/arduino/sketchbook/libraries/DigitecoPower -I/home/pat1/git/rmap/arduino/sketchbook/libraries/Registers -I/home/pat1/git/rmap/arduino/sketchbook/libraries/HYT2X1 -I/home/pat1/git/rmap/arduino/sketchbook/libraries/NTP -I/home/pat1/git/rmap/arduino/sketchbook/libraries/sim800 -I/home/pat1/git/rmap/arduino/sketchbook/libraries/Ethernet2/src -I/home/pat1/git/rmap/arduino/sketchbook/libraries/PCF8563 -I/home/pat1/git/rmap/arduino/sketchbook/libraries/Rmap -I/home/pat1/git/rmap/arduino/sketchbook/libraries/SdFat/src -I/home/pat1/.platformio/packages/framework-arduino-avr/libraries/SPI/src -I/home/pat1/git/rmap/arduino/sketchbook/libraries/ArduinoJson/src -I/home/pat1/git/rmap/arduino/sketchbook/libraries/Time -I/home/pat1/git/rmap/arduino/sketchbook/libraries/LiquidCrystal_I2C -I/home/pat1/.platformio/packages/framework-arduino-avr/libraries/Wire/src -Iinclude -I/home/pat1/.platformio/packages/framework-arduino-avr/cores/arduino -I/home/pat1/.platformio/packages/framework-arduino-avr/variants/microduino_plus src/stima.ino.cpp
avr-g++ -o .pio/build/1284p16m/firmware.elf -Os -mmcu=atmega1284p -Wl,--gc-sections -flto -fuse-linker-plugin .pio/build/1284p16m/src/stima.ino.cpp.o .pio/build/1284p16m/src/stm32_static.c.o -L.pio/build/1284p16m -Wl,--start-group .pio/build/1284p16m/lib0c9/libWire.a .pio/build/1284p16m/liba3f/libLiquidCrystal_I2C.a .pio/build/1284p16m/lib6d7/libTime.a .pio/build/1284p16m/lib8f9/libArduinoJson.a .pio/build/1284p16m/lib6bf/libSPI.a .pio/build/1284p16m/lib9d8/libSdFat.a .pio/build/1284p16m/lib9c2/libRmap.a .pio/build/1284p16m/lib47a/libPCF8563.a .pio/build/1284p16m/lib6a7/libEthernet2.a .pio/build/1284p16m/libf9d/libsim800.a .pio/build/1284p16m/lib743/libNTP.a .pio/build/1284p16m/lib7d0/libHYT2X1.a .pio/build/1284p16m/lib3de/libRegisters.a .pio/build/1284p16m/libe81/libDigitecoPower.a .pio/build/1284p16m/lib255/libSensorDriver.a .pio/build/1284p16m/libd91/libarduinoJsonRPC.a .pio/build/1284p16m/libc1b/libMQTTClient.a .pio/build/1284p16m/lib589/libFreeRTOS.a .pio/build/1284p16m/libFrameworkArduinoVariant.a .pio/build/1284p16m/libFrameworkArduino.a -lm -Wl,--end-group
lto1: internal compiler error: in lto_output_varpool_node, at lto-cgraph.c:624
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://www.atmel.com> for instructions.
lto-wrapper: fatal error: avr-g++ returned 1 exit status
compilation terminated.
/home/pat1/.platformio/packages/toolchain-atmelavr@1.50400.190710/bin/../lib/gcc/avr/5.4.0/../../../../avr/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status
*** [.pio/build/1284p16m/firmware.elf] Error 1

suggestions:

https://github.com/arduino/ArduinoCore-avr/issues/39 https://forum.arduino.cc/index.php?topic=566280.0

[pat1]

obsolete