running-make-to-build

# Overview The build is a recursive make structure, with several projects vendored in to `lib` that use their own Makefiles and also one primary `src/Makefile.am` that defines most of the build. - ALWAYS run `make -j $(nproc)` to get full parallelism - ALWAYS run from the top level directory - ALWAYS run with `2>&1 | tail -N` to limit output - ALWAYS run `git add <somefile> && ./make-mks` after adding `<somefile>` to ensure it is included in the build. - NEVER run from a subdirectory - NEVER run with `make -C <somedir>` for any other directory - NEVER run `cargo` manually, let `make` run it - NEVER edit `Makefile` or `Makefile.in`, only ever edit `Makefile.am` ## Targets The main targets are: - `all` -- the implicit target, builds `src/stellar-core` - `check` -- builds `all` then runs unit and integration tests - `clean` -- removes build artifacts - `format` -- auto-formats source code with standard rules If anything goes wrong or is confusing in the build, start by running `make clean` and trying again. You should have configured with `--enable-ccache` which means that rebuilding will typically be very cheap. Especially if you run with `make -j $(nproc)` ## Rust build The `src/Makefile.am` also delegates to `cargo` to build the rust components of stellar-core in `src/rust` as well as all the submodules in `src/rust/soroban`. The integration is quite subtle. You should always let `src/Makefile.am` handle invoking `cargo`. ## Generated files Several source files are generated. All .x files in `src/protocol-{curr,next}` are turned into .cpp and .h files by the `xdrpp` code-generator in `lib/xdrpp`. Parts of the XDR query system in `src/util/xdrquery` are built by `flex` and `bison`. Files like `src/main/StellarCoreVersion.cpp` bake the current version information into a string constant in stellar-core. And finally the rust bridge `src/rust/RustBridge.{cpp,h}` is generated by the `cxxbridge` tool from `src/rust/bridge.rs`. ## Editing the makefiles Most of the time you won't need to edit `Makefile.am` or `src/Makefile.am` at all. Files included in the build are driven by the script `./make-mks` which lists files tracked by git and defines makefile variables based on them. As soon as you add a .cpp or .h file to git and re-run `./make-mks` it will be added to the build.