Failing to provide any of the required features can provide a message
such as:
There are unsatisfied feature requirements: periph_uart|periph_lpuart
This can be confusing and may hide the actual. E.g. above message
was generated when using SPI on the `msb-430` and `stdio_uart`. However,
the MSB-430 board *does* provide `periph_uart`, so this looks like a bug
in the feature resolution. This changes the failure mode of
`FEATURES_REQUIRED_ANY` to just pick the first of the alternatives
given if none of the alternative is usable, which gives in the example
the following message instead:
The following features may conflict: periph_spi periph_uart
Rationale: Both SPI and UART are provided by the same USART
peripheral
The output is less surprising and can provide non-obvious reasons
why `FEATURES_REQUIRED_ANY` failed to pick a feature. The downside is
that the alternatives are no longer visible. However, that output
likely was so confusing this might be for the best.
Co-authored-by: mguetschow <mikolai.guetschow@tu-dresden.de>
