There's an issue with PROGMEM in glcdfont.c and Adafruit_SSD1351.cpp (Adafruit_GFX, does it right) as well as the bitbanging SPI implementation:
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp: In member function 'void Adafruit_SSD1351::spiwrite(uint8_t)':
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:45: error: base operand of '->' is not a pointer
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:46: error: base operand of '->' is not a pointer
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:56: error: '_BV' was not declared in this scope
...
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp: In member function 'void Adafruit_SSD1351::begin()':
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:267: error: invalid conversion from 'Pio* const' to 'uint8_t'
There's an issue with PROGMEM in glcdfont.c and Adafruit_SSD1351.cpp (Adafruit_GFX, does it right) as well as the bitbanging SPI implementation:
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp: In member function 'void Adafruit_SSD1351::spiwrite(uint8_t)': C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:45: error: base operand of '->' is not a pointer C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:46: error: base operand of '->' is not a pointer C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:56: error: '_BV' was not declared in this scope
...
C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp: In member function 'void Adafruit_SSD1351::begin()': C:\Arduino\libraries\Adafruit_SSD1351\Adafruit_SSD1351.cpp:267: error: invalid conversion from 'Pio* const' to 'uint8_t'