Add dependency generation to Makefile

[urbasus]

Dependency generation makes sure targets are determined out of date should any included headers be out of date.

Tested by rebuilding across changes to cyw43_configport.h.

[dpgeorge]

Thanks for the contribution.

I actually consciously left this out because I wanted to keep the Makefile as simple as possible. I like simplicity!

But I guess it doesn't harm to add it, and it's only a few lines.

[urbasus]

Thanks for the contribution.

I actually consciously left this out because I wanted to keep the Makefile as simple as possible. I like simplicity!

But I guess it doesn't harm to add it, and it's only a few lines.

I usually leave it out too for the same reason. This time felt like a amusing evening challenge. It took me a couple iterations to get right and terse. If only I could remember the incantation for future projects...

Do as you wish. I trust your judgement.

[dpgeorge]

It took me a couple iterations to get right and terse.

Your solution is very neat.

Merged!