-# dup.m4 serial 3
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
+# dup.m4 serial 4
+dnl Copyright (C) 2011-2016 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
REPLACE_DUP=1
fi
])
+ AC_CACHE_CHECK([whether dup works], [gl_cv_func_dup_works],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM([[#include <unistd.h>
+ #include <fcntl.h>
+ #include <errno.h>]],
+ [[/* On OS/2 kLIBC, dup does not work on a directory fd. */
+ int fd = open (".", O_RDONLY);
+ return fd < 0 ? 1 : dup (fd) < 0 ? 2 : 0;
+ ]])
+ ],
+ [gl_cv_func_dup_works=yes],
+ [gl_cv_func_dup_works=no],
+ [gl_cv_func_dup_works='guessing yes'])
+ ])
+ case "$gl_cv_func_dup_works" in
+ *yes) ;;
+ *)
+ REPLACE_DUP=1
+ ;;
+ esac
])
# Prerequisites of lib/dup.c.