This page is about how to build a package for an existing OpenWrt distribution without rebuilding the whole world or using the SDK (because it doesn't work on your host system). The instructions come from the forum topic https://forum.openwrt.org/viewtopic.php?id=29313
git clone https://github.com/openwrt/openwrt.git ./scripts/feeds update make defconfig make package/symlinks
If you get an error at "make defconfig" saying that ncurses.h wasn't found install libncurses5-dev package on your system.
Then copy the config.x86_generic, or whichever you need, from the SDK into .config
make menuconfig make menuconfig -> check nano and libncurses make tools/install make toolchain/install make target/compile ./script/feeds install owhttpd make package/owhttpd/prepare make package/owhttpd/compile make package/owhttpd/install make package/index