From df31fa4a51822faccb35aa7a253c8af015869d0c Mon Sep 17 00:00:00 2001
From: Yuta Saito <kateinoigakukun@gmail.com>
Date: Thu, 9 Dec 2021 12:44:45 +0900
Subject: [PATCH] [wasm] configure.ac: don't require dup and dup2 only for wasi

---
 configure.ac | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 2696d6e76c..e20e133feb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1930,7 +1930,14 @@ AC_DEFUN([RUBY_REQUIRE_FUNC], [
     AS_IF([test "$ac_cv_func_[]AS_TR_SH($1)" = yes], [],
           [AC_MSG_ERROR($1[() must be supported])])
 ])
-m4_map_args_w([dup dup2], [RUBY_REQUIRE_FUNC(], [)])
+
+# dup and dup2 are always available except for WASI
+AS_CASE(["$target_os"],
+    [wasi*], [],
+    [
+        m4_map_args_w([dup dup2], [RUBY_REQUIRE_FUNC(], [)])
+    ]
+)
 
 AC_REPLACE_FUNCS(acosh)
 AC_REPLACE_FUNCS(cbrt)