Vendor dependencies for 0.3.0 release

vendor/alsa-sys/build.rs

@@ -0,0 +1,16 @@
+extern crate pkg_config;
+
+fn main() {
+    if let Err(e) = pkg_config::probe_library("alsa") {
+        match e {
+            pkg_config::Error::Failure { .. } => panic! (
+                "Pkg-config failed - usually this is because alsa development headers are not installed.\n\n\
+                For Fedora users:\n# dnf install alsa-lib-devel\n\n\
+                For Debian/Ubuntu users:\n# apt-get install libasound2-dev\n\n\
+                pkg_config details:\n{}",
+                e
+            ),
+            _ => panic!("{}", e)
+        }
+    }
+}