Test for unicode-enabled libncurses

configure.ac

@@ -146,15 +146,17 @@ fi
 
 AC_ARG_ENABLE(unicode, [AC_HELP_STRING([--enable-unicode], [enable Unicode support])], ,enable_unicode="yes")
 if test "x$enable_unicode" = xyes; then
-   AC_CHECK_LIB([ncursesw6], [refresh], [
+   AC_CHECK_LIB([ncursesw6], [addnwstr], [
       AC_DEFINE(HAVE_LIBNCURSESW, 1, [])
       LIBS="-lncursesw6 $LIBS "
    ], [
-      AC_CHECK_LIB([ncursesw], [refresh], [], [
+      AC_CHECK_LIB([ncursesw], [addnwstr], [], [
+         AC_CHECK_LIB([ncurses], [addnwstr], [], [
             missing_libraries="$missing_libraries libncursesw"
             AC_MSG_ERROR([You may want to use --disable-unicode or install libncursesw.])
          ])
       ])
+   ])
    AC_CHECK_HEADERS([ncursesw/curses.h],[:],
       [AC_CHECK_HEADERS([ncurses/ncurses.h],[:],
          [AC_CHECK_HEADERS([ncurses/curses.h],[:],