diff --git a/core/libjsonnet.cpp b/core/libjsonnet.cpp
index d9654682b..39c0d63a3 100644
--- a/core/libjsonnet.cpp
+++ b/core/libjsonnet.cpp
@@ -16,6 +16,7 @@ limitations under the License.
 
 #include <cstdlib>
 #include <cstring>
+#include <cerrno>
 
 #include <exception>
 #include <fstream>