diff --git a/Utilities/cmcurl/CMakeLists.txt b/Utilities/cmcurl/CMakeLists.txt
index 510851a26..0f98e5a41 100644
--- a/Utilities/cmcurl/CMakeLists.txt
+++ b/Utilities/cmcurl/CMakeLists.txt
@@ -731,6 +731,7 @@ FOREACH(var
     SIZEOF_LONG_LONG
     SIZEOF___INT64
     SIZEOF_SIZE_T
+    SIZEOF_SSIZE_T
     SIZEOF_TIME_T
     )
   IF(NOT ${var}_CODE)