diff --git a/src/shrpx_https_upstream.h b/src/shrpx_https_upstream.h
index bbea055..09787d6 100644
--- a/src/shrpx_https_upstream.h
+++ b/src/shrpx_https_upstream.h
@@ -29,9 +29,7 @@
 
 #include <stdint.h>
 
-extern "C" {
 #include "http-parser/http_parser.h"
-}
 
 #include "shrpx_upstream.h"