Cross-compiling boost for OpenWRT

This post showcases how to cross-compile boost for OpenWRT. We’ll use the Teltonika RUTX10 SDK which is already pre-configured with the relevant OpenWRT settings for that router.

The prerequisite for this is that you have:

• Downloaded the SDK
• Built it using our instructions or the official manual if you prefer a longer read.

We assume the SDK is located in ~/rutos-ipq40xx-rutx-gpl.

Compiling boost

First, you need to consider that many boost libraries are header-only libraries. For those libraries, you don’t need to compile boost, but it might still be easier to prepare a complete boost folder for installation.

First, download boost and unpack it. Now run

./bootstrap.sh

to compile bjam.

Now, open project-config.jam inside the boost folder and add the following line at the top of the file:

using gcc : openwrt : arm-openwrt-linux-muslgnueabi-g++ ;

Now, inside the boost folder, run the following bash script:

export STAGING_DIR=~/rutos-ipq40xx-rutx-gpl/staging_dir
export TOOLCHAIN=${STAGING_DIR}/toolchain-arm_cortex-a7+neon-vfpv4_gcc-8.4.0_musl_eabi
export CC=${TOOLCHAIN}/bin/arm-openwrt-linux-muslgnueabi-gcc
export CPP=${TOOLCHAIN}/bin/arm-openwrt-linux-muslgnueabi-g++
export PATH=$PATH:${TOOLCHAIN}/bin/

# Insert at the top of project-config.jam
# using gcc : openwrt : arm-openwrt-linux-muslgnueabi-g++ ;

rm -rf ~/boost_rutx10
mkdir -p ~/boost_rutx10/
./b2 --prefix=$HOME/boost_rutx10 install toolset=gcc-openwrt -sNO_COMPRESSION=1

Now, boost is installed in ~/boost_rutx10, which has include and lib subdirectories.