Applied the patch.

extconf.rb

@@ -38,8 +38,8 @@
   raise "ncurses header file not found"
 end
 
-if have_library("ncurses", "wmove")
-  curses_lib = "ncurses"
+if have_library("ncursesw", "wmove")
+  curses_lib = "ncursesw"
 elsif have_library("pdcurses", "wmove")
   curses_lib = "pdcurses"
 else
@@ -123,11 +123,11 @@
 
 puts "checking for the panel library..."
 if have_header("panel.h")
-  have_library("panel", "panel_hidden")
+  have_library("panelw", "panel_hidden")
 end
 puts "checking for the form library..."
 if have_header("form.h")
-  have_library("form", "new_form")
+  have_library("formw", "new_form")
 end
 puts "checking for the menu library..."
 if have_header("menu.h")

ncurses_wrap.c

@@ -2726,6 +2726,8 @@ static void init_safe_functions(void)
 }
 void Init_ncurses_bin(void)
 {
+    setlocale(LC_ALL, "");
+
     mNcurses = rb_define_module("Ncurses");
     eNcurses = rb_define_class_under(mNcurses, "Exception", rb_eRuntimeError);
     rb_iv_set(mNcurses, "@windows_hash", rb_hash_new());

ncurses_wrap.h

@@ -83,6 +83,7 @@ int close(int);
 #  endif
 #endif
 
+#include <locale.h>
 #include <ruby.h>
 
 extern VALUE mNcurses;  /* module Ncurses */