MKR1010 compile error with dtostrf(...)

My code compiles with UnoWiFi Rev2 and runs correctly but the same code errors with MKR1010 at code dtostrf(.... )
compile display

UnoWiFi_R2_ThingSpeak_DHTv3.1.ino:281:3: error: 'dtostrf' was not declared in this scope
dtostrf(t1,-7,1,result);//(float value,length of result left justified, num dec, result array)
^~~~~~~

Is there a library that will provide this array formatting function for the MKR1010?

Solved
the fix is
#include <avr/dtostrf.h>

Thanks for taking the time to post an update mackarduino. I'm glad you found a solution. Enjoy!