Use CIRCUITPY_OS_GETENV to guard new feature

Author: RetiredWizard

docs/environment.rst

@@ -181,7 +181,8 @@ Allows the entry of a display scaling factor used during the terminalio console
 The entered scaling factor only affects the terminalio console and has no impact on
 the UART, Web Workflow, BLE Workflow, etc consoles.
 
-This feature is not enabled on some CircuitPython board with limited Flash, currently
-this includes some of the Atmel_samd boards based on the M0 microprocessor.
+This feature is not enabled on boards that the CIRCUITPY_OS_GETENV (os CIRCUIPTY_FULL_BUILD)
+flag has been set to 0. Currently this is primarily boards with limited flash including some
+of the Atmel_samd boards based on the SAMD21/M0 microprocessor.
 
 `boards that the terminalio core module is available on <https://docs.circuitpython.org/en/latest/shared-bindings/terminalio/>`_

supervisor/shared/display.c

@@ -36,8 +36,10 @@
 
 #if CIRCUITPY_TERMINALIO
 #include "supervisor/port.h"
+#if CIRCUITPY_OS_GETENV
 #include "shared-module/os/__init__.h"
 #endif
+#endif
 
 #if CIRCUITPY_REPL_LOGO
 extern uint32_t blinka_bitmap_data[];
@@ -67,7 +69,9 @@ void supervisor_start_terminal(uint16_t width_px, uint16_t height_px) {
     if (width_in_tiles <= 80) {
         scale = 1;
     }
+    #if CIRCUITPY_OS_GETENV
     (void)common_hal_os_getenv_int("CIRCUITPY_TERMINAL_SCALE", &scale);
+    #endif
 
     width_in_tiles = MAX(1, width_px / (scroll_area->tile_width * scale));
     uint16_t height_in_tiles = MAX(2, height_px / (scroll_area->tile_height * scale));