--- a/PositionableStream.st	Thu Oct 24 17:41:35 2019 +0200
+++ b/PositionableStream.st	Fri Oct 25 12:29:42 2019 +0200
@@ -776,6 +776,8 @@
 upTo:anObject
     |anObjectIsCharacter|
 %{
+#include <sys/types.h>
+
     if (__isCharacter(anObject)) {
         unsigned int ch = __intVal(__characterVal(anObject));
         OBJ _coll = __INST(collection);