diff --git a/src/tool_util.c b/src/tool_util.c
index 08fb39706a..ce235e3bd8 100644
--- a/src/tool_util.c
+++ b/src/tool_util.c
@@ -105,7 +105,8 @@ int msdos_ftruncate(int fd, curl_off_t where)
   if(where > INT_MAX)
     return -1;
 
-  return ftruncate(fd, (off_t) where);
+  /* avoid using the macro for this */
+  return (ftruncate)(fd, (off_t) where);
 }
 #endif /* USE_MSDOS_FTRUNCATE */