added docs to remind users to populate the submodules

README.md

@@ -14,3 +14,17 @@ This is the home for [llama-cpp-2][crates.io]. It also contains the [llama-cpp-s
 This project was created with the explict goal of staying as up to date as possible with llama.cpp, as a result it is dead simple, very close to raw bindings, and does not follow semver meaningfully.
 
 Check out the [docs.rs] for crate documentation or the [readme] for high level information about the project.
+
+## Hacking
+
+Ensure that when you clone this project you also clone the submodules. This can be done with the following command:
+
+```sh
+git clone --recursive https://github.com/utilityai/llama-cpp-rs
+```
+
+or if you have already cloned the project you can run:
+
+```sh
+git submodule update --init --recursive
+```

llama-cpp-sys-2/build.rs

@@ -1,11 +1,16 @@
 use std::env;
 use std::path::PathBuf;
+use std::path::Path;
 
 fn main() {
     println!("cargo:rerun-if-changed=llama.cpp");
 
     let cublas_enabled = env::var("CARGO_FEATURE_CUBLAS").is_ok();
 
+    if !Path::new("llama.cpp/ggml.c").exists() {
+    	panic!("llama.cpp seems to not be populated, try running `git submodule update --init --recursive` to init.")
+    }
+
     let mut ggml = cc::Build::new();
     let mut ggml_cuda = if cublas_enabled { Some(cc::Build::new()) } else { None };
     let mut llama_cpp = cc::Build::new();