[root@VM_129_51_centos openwrt]# wget http://downloads.openwrt.org/snapshots/trunk/ramips/mt7620/OpenWrt-Toolchain-ramips-mt7620_gcc-5.3.0_musl-1.1.15.Linux-x86_64.tar.bz2

[root@VM_129_51_centos openwrt]# tar -jxf OpenWrt-Toolchain-ramips-mt7620_gcc-5.3.0_musl-1.1..Linux-x86_64.tar.bz2

[root@VM_129_51_centos openwrt]# mv OpenWrt-Toolchain-ramips-mt7620_gcc-5.3.0_musl-1.1..Linux-x86_64 toolchain

[root@VM_129_51_centos openwrt]# wget http://downloads.openwrt.org/chaos_calmer/15.05.1/ramips/mt7620/OpenWrt-SDK-15.05.1-ramips-mt7620_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-x86_64.tar.bz2

[root@VM_129_51_centos openwrt]# tar -jxf OpenWrt-SDK-15.05.-ramips-mt7620_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-x86_64.tar.bz2

[root@VM_129_51_centos openwrt]# mv OpenWrt-SDK-15.05.1-ramips-mt7620_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-x86_64 SDK

[root@VM_129_51_centos openwrt]# find / -name staging_dir

/root/openwrt/SDK/staging_dir

[root@VM_129_51_centos bin]# export STAGING_DIR='/root/openwrt/SDK/staging_dir'

[root@VM_129_51_centos bin]# export CC=/root/openwrt/toolchain/toolchain-mipsel_24kec+dsp_gcc-5.3.0_musl-1.1./bin/mipsel-openwrt-linux-musl-g++

[root@VM_129_51_centos bin]# export CPLUS_INCLUDE_PATH=/root/openwrt/SDK/build_dir/target-mipsel_24kec+dsp_uClibc-0.9.33.2/linux-ramips_mt7620/linux-3.18.23/include/uapi/linux/can/

[root@VM_129_51_centos bin]# export LD_FLAGS=-L/root/openwrt/toolchain/toolchain-mipsel_24kec+dsp_gcc-5.3.0_musl-1.1.15/lib/  -static-libstdc++ -static-libgcc -lgcc_s