Fixes String(float) issue with Stack Smashing

Author: SuGlider

Diff for: cores/esp32/stdlib_noniso.c

@@ -88,7 +88,7 @@ char* ultoa(unsigned long value, char* result, int base) {
     return result;
 }
 
-char * dtostrf(double number, signed char width, unsigned int prec, char *s) {
+char * dtostrf(double number, signed int width, unsigned int prec, char *s) {
     bool negative = false;
 
     if (isnan(number)) {

Diff for: cores/esp32/stdlib_noniso.h

@@ -39,7 +39,7 @@ char* utoa (unsigned int val, char *s, int radix);
 
 char* ultoa (unsigned long val, char *s, int radix);
 
-char* dtostrf (double val, signed char width, unsigned int prec, char *s);
+char* dtostrf (double val, signed int width, unsigned int prec, char *s);
 
 #ifdef __cplusplus
 } // extern "C"