diff --git a/src/external/e57/include/E57Format.h b/src/external/e57/include/E57Format.h
index 5c3195e..1aa849b 100644
--- a/src/external/e57/include/E57Format.h
+++ b/src/external/e57/include/E57Format.h
@@ -32,6 +32,7 @@
 //! @file  E57Format.h header file for the E57 API
 
 #include <cfloat>
+#include <cstdint>
 #include <memory>
 #include <vector>