Add '_STDINT_H' to list of defines which indicate stdint.h included.

[rthille]

The ESP8266 #define for stdint.h is _STDINT_H. Added here to avoid warning during compile. https://github.com/esp8266/Arduino/blob/master/tools/sdk/libc/xtensa-lx106-elf/include/stdint.h

Should only affect warning during compile; no behavior change to produced code.

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[ladyada]

please run clang-format so this passes CI :) https://github.com/adafruit/Adafruit_VL53L0X/runs/612918161#step:7:13

[ladyada]

gr8 thanx!