board/sunxi/board.c: In function ‘mmc_get_env_dev’:
board/sunxi/board.c:535:24: error: ‘CONFIG_SYS_MMC_ENV_DEV’ undeclared (first use in this function)
  535 |                 return CONFIG_SYS_MMC_ENV_DEV;
      |                        ^~~~~~~~~~~~~~~~~~~~~~
board/sunxi/board.c:535:24: note: each undeclared identifier is reported only once for each function it appears in
board/sunxi/board.c:537:1: warning: control reaches end of non-void function [-Wreturn-type]
  537 | }
      | ^
make[3]: *** [scripts/Makefile.build:257: board/sunxi/board.o] Error 1
make[2]: *** [Makefile:1858: board/sunxi] Error 2
make[2]: *** Waiting for unfinished jobs....
  CC      boot/pxe_utils.o
  CC      arch/arm/mach-sunxi/clock_sun6i.o
  CC      arch/arm/mach-sunxi/timer.o
  CC      arch/arm/lib/cache-cp15.o
  CC      arch/arm/lib/psci-dt.o
  AS      arch/arm/lib/bitops.o
  AS      arch/arm/lib/ashldi3.o
  AS      arch/arm/lib/ashrdi3.o
  CC      arch/arm/lib/div0.o
  AS      arch/arm/lib/div64.o
  AS      arch/arm/lib/lib1funcs.o
  CC      boot/image.o
  AS      arch/arm/lib/lshrdi3.o
  AS      arch/arm/lib/muldi3.o
  AR      arch/arm/mach-sunxi/built-in.o
  AS      arch/arm/lib/uldivmod.o
  CC      arch/arm/lib/eabi_compat.o
  AR      arch/arm/lib/built-in.o
  CC      boot/image-board.o
  CC      boot/bootdev-uclass.o
  CC      boot/bootflow.o
  CC      boot/bootmeth-uclass.o
  CC      boot/bootstd-uclass.o
  AR      arch/arm/lib/lib.a
  CC      boot/bootmeth_extlinux.o
  CC      boot/fdt_support.o
  CC      boot/image-fdt.o
  CC      boot/image-fit.o
  CC      boot/expo.o
  CC      boot/scene.o
  CC      boot/expo_build.o
  CC      boot/scene_menu.o
  CC      boot/scene_textline.o
  CC      boot/vbe.o
  CC      boot/vbe_request.o
  CC      boot/vbe_simple.o
  CC      boot/vbe_simple_os.o
  AR      boot/built-in.o
make[1]: *** [package/pkg-generic.mk:283: /home/peter/buildroot-2024.02.1/output/speedsaver/build/uboot-2024.01/.stamp_built] Error 2
make: *** [Makefile:23: _all] Error 2
peter@asus:~/buildroot-2024.02.1/output/speedsaver$