在Buildroot上为一个Beaglebone Black目标构建一个根文件系统。使用crosstool-NG工具链与buildroot，我在buildroot中得到了这个错误。
>>> toolchain-external-custom Configuring
Incorrect selection of kernel headers: expected 4.2.x, got 4.20.x
john@vmpc:/home/emmet/Downloads/crosstool-ng-1.24.0$ arm-cortex_a8-linux-gnueabihf-gcc -v
Using built-in specs.
COLLECT_GCC=arm-cortex_a8-linux-gnueabihf-gcc
COLLECT_LTO_WRAPPER=/home/emmet/x-tools/arm-cortex_a8-linux-gnueabihf/libexec/gcc/arm-cortex_a8-linux-gnueabihf/8.3.0/lto-wrapper
Target: arm-cortex_a8-linux-gnueabihf
Configured with: /home/emmet/Downloads/crosstool-ng-1.24.0/.build/arm-cortex_a8-linux-gnueabihf/src/gcc/configure --build=x86_64-build_pc-linux-gnu --host=x86_64-build_pc-linux-gnu --target=arm-cortex_a8-linux-gnueabihf --prefix=/home/emmet/x-tools/arm-cortex_a8-linux-gnueabihf --with-sysroot=/home/emmet/x-tools/arm-cortex_a8-linux-gnueabihf/arm-cortex_a8-linux-gnueabihf/sysroot --enable-languages=c,c++ --with-cpu=cortex-a8 --with-fpu=vfpv3 --with-float=hard --with-pkgversion='crosstool-NG 1.24.0' --enable-__cxa_atexit --disable-libmudflap --disable-libgomp --disable-libssp --disable-libquadmath --disable-libquadmath-support --disable-libsanitizer --disable-libmpx --with-gmp=/home/emmet/Downloads/crosstool-ng-1.24.0/.build/arm-cortex_a8-linux-gnueabihf/buildtools --with-mpfr=/home/emmet/Downloads/crosstool-ng-1.24.0/.build/arm-cortex_a8-linux-gnueabihf/buildtools --with-mpc=/home/emmet/Downloads/crosstool-ng-1.24.0/.build/arm-cortex_a8-linux-gnueabihf/buildtools --with-isl=/home/emmet/Downloads/crosstool-ng-1.24.0/.build/arm-cortex_a8-linux-gnueabihf/buildtools --enable-lto --with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm' --enable-threads=posix --enable-target-optspace --enable-plugin --enable-gold --disable-nls --disable-multilib --with-local-prefix=/home/emmet/x-tools/arm-cortex_a8-linux-gnueabihf/arm-cortex_a8-linux-gnueabihf/sysroot --enable-long-long
Thread model: posix
gcc version 8.3.0 (crosstool-NG 1.24.0)
有什么办法可以解决这个问题吗？
当在Buildroot中使用自定义的外部工具链时，你必须告诉Buildroot使用了哪些内核头文件来构建工具链。
只要输入 make menuconfig -> Toolchain ->。External toolchain kernel headers series 来设置它。