In#208 I added pragmas to suppress deprecation warnings related to sprintf that were added in newer versions of GCC and CLang, and which caused compilation failure. These suppressions should be removed.

One usage is in the test suite's implemention ofitoa that is needed to run String tests. I have a quick fix for that relying onsnprintf but I also thought of just using a more basic implementation ofitoa such as the one from K&R or even just copying the implementation from the SAMD core.

Thinking a bit deeper though, the only use in API code is inString and it looks to be unnecessarily double buffering during those conversions. I think there's an opportunity to remove String's dependency onitoa and make it more efficient, which would also eliminate the need for an implementation ofitoa in the test suite. I plan to look in to that approach.

A similar use is in the test suite's implementation ofdtostrf which delegates the deprecated avr impl. For that, I thinkString can be improved to avoid the double buffering although it would still delegate to the core for the conversion, assuming the core may have implementation-specific FP support.

The final use was inIPAddress and that looks like it can simply be changed to usedsnprintf