现象：
################ parallel build environment end ##################
shell is /bin/sh. Bash version is 4.2.46(2)-release
****************************************************
ERROR: could not find Toolchain
/opt/toolchains//crosstools-arm-gcc-5.5-linux-4.1-glibc-2.26-binutils-2.28.1
****************************************************
make[1]: *** [prebuild_checks] Error 1
make[1]: Leaving directory `/home/wangxinyu/work/AX1803/6755_sdk'
make: *** [default] Error 2
解决方法：
# tar -xvf crosstools-arm-gcc-5.5-linux-4.1-glibc-2.26-binutils-2.28.1.bz2 -C /opt/
# mkdir -p /opt/toolchains/
# mv /opt/projects/hnd/tools/bcm/crosstools-arm-gcc-5.5-linux-4.1-glibc-2.26-binutils-2.28.1 /opt/toolchains/
