有點愚蠢，記錄一下，先編過去，然後再把 x86_64-linux-gnu 移回來，估計是我環境變量髒了。
juwan@juwan-n85-dls:~/v831/out/v831-sipeed/compile_dir/target/pypi/Pillow-7.2.0$ cd "/home/juwan/v831/out/v831-sipeed/compile_dir/target/pypi/Pillow-7.2.0/" && CC="/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/bin/arm-openwrt-linux-muslgnueabi-gcc" CCSHARED="/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/bin/arm-openwrt-linux-muslgnueabi-gcc -fpic" CXX="arm-openwrt-linux-muslgnueabi-g++" LD="/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/bin/arm-openwrt-linux-muslgnueabi-gcc" LDSHARED="/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/bin/arm-openwrt-linux-muslgnueabi-gcc -shared" CFLAGS="-Os -pipe -march=armv7-a -mtune=cortex-a7 -mfpu=neon -fno-caller-saves -Wno-unused-result -mfloat-abi=hard -Wformat -Werror=format-security -fstack-protector -D_FORTIFY_SOURCE=1 -Wl,-z,now -Wl,-z,relro" CPPFLAGS="-I/home/juwan/v831/out/v831-sipeed/staging_dir/target/usr/include -I/home/juwan/v831/out/v831-sipeed/staging_dir/target/include -I/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/usr/include -I/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/include -I/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/include/fortify -I/home/juwan/v831/out/v831-sipeed/staging_dir/target/usr/include/python3.8" LDFLAGS="-L/home/juwan/v831/out/v831-sipeed/staging_dir/target/usr/lib -L/home/juwan/v831/out/v831-sipeed/staging_dir/target/lib -L/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/usr/lib -L/home/juwan/v831/prebuilt/gcc/linux-x86/arm/toolchain-sunxi-musl/toolchain/lib -znow -zrelro -lpython3.8" _PYTHON_HOST_PLATFORM="linux-arm" __PYVENV_LAUNCHER__="/usr/bin/python3.8" PYTHONPATH="/home/juwan/v831/out/v831-sipeed/staging_dir/target/usr/lib/python3.8:/home/juwan/v831/out/v831-sipeed/staging_dir/target//usr/lib/python3.8/site-packages:/home/juwan/v831/out/v831-sipeed/compile_dir/target/pypi/Pillow-7.2.0/ipkg-install//usr/lib/python3.8/site-packages" PYTHONDONTWRITEBYTECODE=1 PYTHONOPTIMIZE="" _python_sysroot="/home/juwan/v831/out/v831-sipeed/staging_dir/target" _python_prefix="/usr" _python_exec_prefix="/usr" /home/juwan/v831/out/v831-sipeed/staging_dir/target/host/bin/python3.8 setup.py build_ext --enable-zlib --enable-jpeg --enable-freetype --disable-lcms --disable-webp --disable-webpmux --disable-jpeg2000 --disable-imagequant --disable-platform-guessing install --prefix="/usr" --root="/home/juwan/v831/out/v831-sipeed/compile_dir/target/pypi/Pillow-7.2.0/ipkg-install"