ngram-mod : fix build [no ci] (#19216)

diff --git a/common/ngram-mod.h b/common/ngram-mod.h
index cf3c89c915d9180ac6f39350e08cf408a5e448aa..7af92e9dde4a10ec088cf1612f1881b869cfac02 100644 (file)
--- a/common/ngram-mod.h
+++ b/common/ngram-mod.h
@@ -2,6 +2,7 @@
 
 #include <cstdint>
 #include <vector>
+#include <cstddef>
 
 //
 // common_ngram_mod