Add NuttX support for running DirectFB apps on MCU devices

[caramelli]

No description provided.

[acassis]

Hi @caramelli I think we need include support on NuttX Apps mainline to download and compile some demos with DirectFB! ;-)

BTW, you have nice good candidates to be integrated there (TinyGLUT, fbmark, etc)

[caramelli]

Thanks for your consideration for DirectFB on NuttX: the idea is to have an apps/examples/DirectFB/ directory with the code available at DirectFB-examples

The core library can currently be integrated and compiled simply by copying DirectFB2 into the NuttX apps/graphics/ directory.

Running DirectFB2 applications on NuttX also requires a system module based on the NuttX Framebuffer interface (nuttx/video/fb.h): work still in progress on this part and some fixes needed before pushing.

[acassis]

Thank you for update @caramelli!
I opened an enhancement issue to include DirectFB on NuttX apps: apache/nuttx-apps#1742

Maybe we could include a simple SIMulation support like we have to LVGL:
https://nuttx.apache.org/docs/latest/platforms/sim/sim/index.html#running-lvgl

This any everybody could test it without using a supported board :-)