irq commit: this large commit gets interrupts working

Signed-off-by: Sean Cross <sean@xobs.io>

build.rs

@@ -0,0 +1,19 @@
+// NOTE: Adapted from cortex-m/build.rs
+use std::env;
+use std::fs;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+
+    // Put the linker script somewhere the linker can find it
+    fs::File::create(out_dir.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out_dir.display());
+
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=memory.x");
+}