MESHTASTIC_EXCLUDE_ENVIRONMENTAL_SENSOR questions

[oseiler2]

I had a look into creating a minimised build and tried using '#define MESHTASTIC_EXCLUDE_ENVIRONMENTAL_SENSOR'. Not sure if the intention behind the PR #3337 was just disabling the modules, or also excluding the sensor libraries.

If I understand correctly currently the main effect is that it excludes the EnvironmentTelemetryModule and AirQualityTelemetryModule. But the sources under modules/Telemetry/Sensor get still pulled in and compiled, as does all the library dependencies, effectively not really reducing the build size much.

The libraries get included in [environmental_base], which is then included in the various /arch/*.ini files.

1. Excluding [environmental_base] leads to compiler errors, and would also need either
   #if !MESHTASTIC_EXCLUDE_ENVIRONMENTAL_SENSOR statements in all the Sensor sources, or a build_src_filter based exclusion. Some sensors are used for Telemetry and would need #if HAS_TELEMETRY which probably means a build_src_filter won't really work that well without refactoring them.
2. AccelerometerThread uses sensors that have their libs included in [environmental_base]. Should the AccelerometerThread also be excluded when MESHTASTIC_EXCLUDE_ENVIRONMENTAL_SENSOR is defined?
3. Currently QMC5883LCompass is not included under [environmental_base] - should it be moved there?

Happy to create a PR, but would like some feedback first where this should be heading to.

[thebentern]

IMO, if we're excluding environmental sensors to minimize the build, I think it's safe to assume that we don't care about accelerometers or other peripherals.

[oseiler2]

PR #3776