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
./scripts/feeds install owhttpd
make package/owhttpd/prepare
make package/owhttpd/compile
make package/owhttpd/install

make package/index