Add support for Arduino (atmel based boards)

[freol35241]

Describe the feature

Trying to compile for one of the atmel based arduino boards currently error out with "Platform unknown".

[cguimaraes]

Can you provide more details on how are you compiling your project?
Depending on how you do it, you might need to define additional environment flags.

[freol35241]

Hi, I am using a platformio setup defined as following (platformio.ini):

platform = atmelavr
board = yun
framework = arduino
lib_deps = https://github.com/eclipse-zenoh/zenoh-pico#0.7.0-rc

And I am trying to compile the z_scout.ino example from this repository.

The compile error originates from here which lead me to extra_script.py which only seems to support the espressif32 platform for the arduino framework.

Perhaps there is just a need for a set of different environment flags for the atmelavr platform?