diff --git a/lib/config-amigaos.h b/lib/config-amigaos.h
index 14f3a0448b..b7356c7629 100644
--- a/lib/config-amigaos.h
+++ b/lib/config-amigaos.h
@@ -71,6 +71,10 @@
 #define SIZEOF_INT 4
 #define SIZEOF_SIZE_T 4
 
+#ifndef SIZEOF_CURL_OFF_T
+#define SIZEOF_CURL_OFF_T 8
+#endif
+
 #define USE_MANUAL 1
 #define CURL_DISABLE_LDAP 1