diff --git a/sim/mcuboot-sys/build.rs b/sim/mcuboot-sys/build.rs
index 5f5eeac..ebff3c5 100644
--- a/sim/mcuboot-sys/build.rs
+++ b/sim/mcuboot-sys/build.rs
@@ -81,6 +81,7 @@
     conf.file("csupport/run.c");
     conf.include("../../boot/bootutil/include");
     conf.include("../../boot/zephyr/include");
+    conf.include("csupport");
     conf.debug(true);
     conf.flag("-Wall");
     conf.flag("-Werror");