BusyBox + Emscripten + nanozip + diff3

Inspired by https://github.com/tbfleming/em-busybox and https://github.com/tbfleming/em-shell, this repo contains build script of BusyBox for WebAssembly without being a full fork of BusyBox, so upgrading to a new version of BusyBox is easier.

In addition to BusyBox build script, this repo also contains two custom BusyBox applets:

• nanozip - miniz-based imitation of zip utility: busybox nanozip [-r] [[-x EXCLUDED_PATH] ...] OUTPUT_NAME.zip INPUT_PATH [...].
• diff3 - OpenBSD-based implementation of diff3: busybox diff3 [-exEX3] /tmp/d3a.?????????? /tmp/d3b.?????????? file1 file2 file3

em-shell.c, em-shell.h, em-shell.js, arch/em/Makefile are taken from excellent tbfleming/em-shell and tbfleming/em-busybox by Todd Fleming.

Patches not used for now:

• https://github.com/tbfleming/em-busybox/commit/8c592ed5e13a7c35e0e318112bbdbc281798b6d7
• https://github.com/tbfleming/em-busybox/commit/5fbe7c016af61b21c073652fed3b4ee4d744238d

# native version 
make build/native/busybox

# wasm version
make build/wasm/busybox_unstripped.js