diff --git a/.gitmodules b/.gitmodules
index 2632a03..e69de29 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +0,0 @@
-[submodule "cxx/quickjs"]
-  path = cxx/quickjs
-  url = https://github.com/ekibun/quickjs.git
\ No newline at end of file
diff --git a/cxx/quickjs b/cxx/quickjs
deleted file mode 160000
index 1f6ce20..0000000
--- a/cxx/quickjs
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 1f6ce203c6f8cdea33386ac464d5ed19a17aaf9f
diff --git a/cxx/quickjs.cmake b/cxx/quickjs.cmake
index b368134..209b238 100644
--- a/cxx/quickjs.cmake
+++ b/cxx/quickjs.cmake
@@ -1,5 +1,6 @@
 cmake_minimum_required(VERSION 3.7 FATAL_ERROR)
 set(CXX_LIB_DIR ${CMAKE_CURRENT_LIST_DIR})
+set(CMAKE_CXX_STANDARD 20)
 
 # quickjs
 set(QUICK_JS_LIB_DIR ${CXX_LIB_DIR}/quickjs)
@@ -9,6 +10,7 @@ add_library(quickjs STATIC
     ${QUICK_JS_LIB_DIR}/libregexp.c
     ${QUICK_JS_LIB_DIR}/libunicode.c
     ${QUICK_JS_LIB_DIR}/quickjs.c
+    ${QUICK_JS_LIB_DIR}/libbf.c
 )
 
 project(quickjs LANGUAGES C)