PlatformIO User notes:

It is possible to load settings from the calling program rather than modifying
the library for each project by modifying the "platformio.ini" file.

The User_Setup_Select.h file will not load the user setting header files if
USER_SETUP_LOADED is defined.

Instead of using #define, use the -D prefix, for example:

[env:esp32dev]
platform = https://github.com/platformio/platform-espressif32.git#feature/stage
board = esp32dev
framework = arduino
upload_port = ESP32-Test-2481CE9C.local

build_flags =
  -Os
  -DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_DEBUG
  -DUSER_SETUP_LOADED=1
  -DILI9163_DRIVER=1
  -DTFT_WIDTH=128
  -DTFT_HEIGHT=160
  -DTFT_MISO=19
  -DTFT_MOSI=23
  -DTFT_SCLK=18
  -DTFT_CS=5
  -DTFT_DC=19
  -DTFT_RST=-1
  -DLOAD_GLCD=1
  -DSPI_FREQUENCY=27000000

lib_extra_dirs = B:\Projects\ESP32\ESP32Lib