Fix compile error: arm-none-eabi-ld: (remoteproc_virtio.o): in function `metal_io_read': metal/io.h:252: undefined reference to `__atomic_load_8' arm-none-eabi-ld: (remoteproc_virtio.o): in function `metal_io_write': metal/io.h:290: undefined reference to `__atomic_store_8' Not all 32-bit architectures support 64bit atomic, gcc/clang toolchains have built-in properties to indicate whether support atomic64: | $ arm-none-eabi-gcc -march=armv7e-m -dM -E - < /dev/null | grep SYNC | #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1 | #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1 | #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1 Signed-off-by: chao an <anchao@lixiang.com>
