Change compiler option

[NicoHood]

It would be nice if you could change the compiler to avr-g++ instead of avr-gcc for example. This is currently not working. I found an example online which might be similar to what we want to also use:

CXX = $(CROSS_COMPILE)-g++
CC = $(CROSS_COMPILE)-gcc
AS = $(CROSS_COMPILE)-as
AR = $(CROSS_COMPILE)-ar
NM = $(CROSS_COMPILE)-nm
LD = $(CROSS_COMPILE)-ld
OBJDUMP = $(CROSS_COMPILE)-objdump
OBJCOPY = $(CROSS_COMPILE)-objcopy
RANLIB = $(CROSS_COMPILE)-ranlib
STRIP = $(CROSS_COMPILE)-strip

This way we can always overwrite the CC or CXX compiler from avr-gcc to avr-g++. Also wouldnt it make sense to use avr-g++ for c++ files anyways? And if at least 1 c++ source was used, the LD should also be avr-g++?