[platformio]: prevent compile samples directory

[dudanov]

Hi. Thanks for your work!

This simple patch fixes an issue with compiling source files in the examples directory when the directory name is different from examples, in this case samples.

The default value of srcDir is src, with a fallback to the recursive .. This means that the samples directory is also considered a source directory by the Platformio builder. This patch safely defines srcDir as include, which solves the issue.

For example, when building a project for the native platform, compiling the samples/Arduino example results in a logical error about the missing header file Arduino.h.

Compiling .pio\build\native\libd8e\plog\samples\Arduino\src\main.o
.pio\libdeps\native\plog\samples\Arduino\src\main.cpp:1:10: fatal error: Arduino.h: No such file or directory

*****************************************************************
* Looking for Arduino.h dependency? Check our library registry!
*
* CLI  > platformio lib search "header:Arduino.h"
* Web  > https://registry.platformio.org/search?q=header:Arduino.h
*
*****************************************************************

    1 | #include <Arduino.h>
      |          ^~~~~~~~~~~
compilation terminated.

Perhaps this issue could be more effectively addressed in the Platformio build system by adding the example directories from the examples key of library.json to the compilation exceptions. However, this solution will allow you to work around the issue for now.

Thanks.

[SergiusTheBest]

Thank you for the PR!

The behavior is unexpected and looks like a bug in platformio build system or their documentation.