Nested Base Environments in platformio.ini

[fazerlicourice7]

• [ X] Feature Request. Add the ability to have nested base environments in platformio.ini. For example:

  
  [env]
  platform = teensy
  board = teensy41
  framework = arduino

[env:cryo] lib_deps = adafruit/Adafruit MCP9600 Library@^1.1.1

[env:cryo:E1_coldflow] src_filter = -<*> + build_flags = -DHAL=teensy

[env:cryo:E1_coldflow_v2] src_filter = -<*> + build_flags = -DHAL=teensy

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### Additional info

Currently, the single default env is pretty restrictive, I'd like the ability to dynamically change dependencies w/out having to change the dependencies on every single image. Additionally this is very useful for doing embedded vs native (w/ a HAL) development.

[ivankravets]

You need https://docs.platformio.org/en/latest/projectconf/section_env_advanced.html#extends