diff --git a/include/common/h2.h b/include/common/h2.h
index 2927011..c4b0083 100644
--- a/include/common/h2.h
+++ b/include/common/h2.h
@@ -178,6 +178,7 @@
 /* various protocol processing functions */
 
 int h2_make_h1_request(struct http_hdr *list, char *out, int osize, unsigned int *msgf);
+int h2_make_h1_trailers(struct http_hdr *list, char *out, int osize);
 int h2_parse_cont_len_header(unsigned int *msgf, struct ist *value, unsigned long long *body_len);
 int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *msgf);
 int h2_make_htx_response(struct http_hdr *list, struct htx *htx, unsigned int *msgf);