For those who compile Openwork & APRX themselves here a few pointers, in case you run into specific errors.
With special thanks to Wladimir, EW8BAK.
If the error indicates that you have certain ax25 files not available, solve this as follows:
Install libax25-dev (sudo apt-get install libax25-dev)
Now copy the directory /usr/include/netax25 to the openwrt/staging_dir/target-mipsel_mips32_musl-1.1.14/usr/include directory
Next find sockaddr.h and copy the whole directory in which sockaddr.h resides (named bits) also to openwrt/staging_dir/target-mipsel_mips32_musl-1.1.14/usr/include.
Now Openwork should compile, or if you just want to compile aprx, do
make package/aprx/compile -j1 V=s