README.md

@@ -34,12 +34,14 @@ sudo pacman -S webrtc-audio-processing # Arch
 
 ### Build from source
 
+The webrtc source code is included as a git submodule. Be sure to clone this repo with the `--recursive` flag, or pull the submodule with `git submodule update --init`.
+
 Building from source and static linking can be enabled with the `bundled` feature flag. You need the following tools to build from source:
 
 * `clang` or `gcc`
-* `autotools`
-* `libtoolize` (typically `glibtoolize` on MacOS)
-* `pkg-config`
+* `autotools` (MacOS: `brew install automake`, `brew install autoconf`)
+* `libtoolize` (typically `glibtoolize` on MacOS: `brew install libtool`)
+* `pkg-config` (MacOS: `brew install pkg-config`)
 
 ## Contributing
 

webrtc-audio-processing-sys/build.rs

@@ -53,7 +53,8 @@ mod webrtc {
 #[cfg(feature = "bundled")]
 mod webrtc {
     use super::*;
-    use std::process::Command;
+    use failure::bail;
+    use std::{path::Path, process::Command};
 
     const BUNDLED_SOURCE_PATH: &str = "./webrtc-audio-processing";
     const BUNDLED_SOURCE_PATH_ABSEIL: &str = "./abseil-cpp";
@@ -65,6 +66,15 @@ mod webrtc {
     }
 
     pub(super) fn build_if_necessary() -> Result<(), Error> {
+        if Path::new(BUNDLED_SOURCE_PATH).read_dir()?.next().is_none()
+            || Path::new(BUNDLED_SOURCE_PATH_ABSEIL).read_dir()?.next().is_none()
+        {
+            eprintln!("The webrtc-audio-processing or abseil-cpp source directory is empty.");
+            eprintln!("See the crate README for installation instructions.");
+            eprintln!("Remember to clone the repo recursively if building from source.");
+            bail!("Aborting compilation because bundled source directory is empty.");
+        }
+
         let build_dir = out_dir();
         let install_dir = out_dir();