diff --git a/sim/build.rs b/sim/build.rs
new file mode 100644
index 0000000..c69c09a
--- /dev/null
+++ b/sim/build.rs
@@ -0,0 +1,15 @@
+// Build the library.
+
+extern crate gcc;
+
+fn main() {
+    let mut conf = gcc::Config::new();
+
+    conf.file("../boot/bootutil/src/loader.c");
+    conf.file("../boot/bootutil/src/bootutil_misc.c");
+    conf.file("csupport/run.c");
+    conf.include("../boot/bootutil/include");
+    conf.include("../zephyr/include");
+    conf.debug(true);
+    conf.compile("libbootutil.a");
+}