Add AM_LANGINFO_CODESET to support old autotools

configure.ac

@@ -452,6 +452,19 @@ AC_CHECK_HEADERS(locale.h, [],
 ################################
 # Check for CODESET within nl_langinfo
 ################################
+AC_DEFUN([AM_LANGINFO_CODESET],
+[
+  AC_CACHE_CHECK([for nl_langinfo and CODESET], [am_cv_langinfo_codeset],
+    [AC_TRY_LINK([#include <langinfo.h>],
+      [char* cs = nl_langinfo(CODESET); return !cs;],
+      [am_cv_langinfo_codeset=yes],
+      [am_cv_langinfo_codeset=no])
+    ])
+  if test $am_cv_langinfo_codeset = yes; then
+    AC_DEFINE([HAVE_LANGINFO_CODESET], [1],
+      [Define if you have <langinfo.h> and nl_langinfo(CODESET).])
+  fi
+])
 AM_LANGINFO_CODESET
 
 ################################