changed pgm_read_word to pgm_read_ptr when reading pointers

[hallofreunde12]

Hi there,

changing pgm_read_word to pgm_read_ptr when reading pointers in the generated/exported code should make it work with both 8 and 32bit architecture.

Tested with ESP32 D1 Mini and Arduino Nano.

Cheers and thank you for making me able to make my own clock