diff --git a/ChangeLog b/ChangeLog
index 161b4f16c9..5ec4c5d723 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,25 @@
+Mon Dec 17 17:06:56 2001  Nobuyoshi Nakada  <nobu.nakada@nifty.ne.jp>
+
+	* intern.h: add prototypes.
+	  rb_str_dup_frozen()
+
+	* ruby.h: added declaration.
+	  rb_defout, rb_stdin, rb_stdout, rb_stderr, ruby_errinfo
+
+	* rubyio.h: changed double include guard macro to RUBYIO_H.
+
+	* array.c (inspect_call): make static.
+
+	* eval.c (dvar_asgn): ditto.
+
+	* io.c (rb_io_close_read): ditto.
+
+	* lex.c (rb_reserved_word): ditto.
+
+	* ruby.c: (req_list_head, req_list_last): ditto.
+
+	* ruby.c (require_libraries): ditto.
+
 Thu Dec 13 10:03:18 2001  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* time.c (time_cmp): should handle Bignums.
diff --git a/array.c b/array.c
index 9f6d23115e..f1e8eb94cf 100644
--- a/array.c
+++ b/array.c
@@ -797,7 +797,7 @@ struct inspect_arg {
     VALUE arg1, arg2;
 };
 
-VALUE
+static VALUE
 inspect_call(arg)
     struct inspect_arg *arg;
 {
diff --git a/eval.c b/eval.c
index e0d4e9b772..7ee5d5ed5e 100644
--- a/eval.c
+++ b/eval.c
@@ -694,7 +694,7 @@ dvar_asgn_internal(id, value, curr)
     }
 }
 
-void
+static void
 dvar_asgn(id, value)
     ID id;
     VALUE value;
diff --git a/intern.h b/intern.h
index 1febccba98..1101c18b92 100644
--- a/intern.h
+++ b/intern.h
@@ -318,6 +318,7 @@ VALUE rb_tainted_str_new2 _((const char*));
 VALUE rb_obj_as_string _((VALUE));
 VALUE rb_str_to_str _((VALUE));
 VALUE rb_str_dup _((VALUE));
+VALUE rb_str_dup_frozen _((VALUE));
 VALUE rb_str_plus _((VALUE, VALUE));
 VALUE rb_str_times _((VALUE, VALUE));
 VALUE rb_str_substr _((VALUE, long, long));
diff --git a/io.c b/io.c
index 93de16d94c..950d3fa1c6 100644
--- a/io.c
+++ b/io.c
@@ -1101,7 +1101,7 @@ rb_io_closed(io)
     return (fptr->f || fptr->f2)?Qfalse:Qtrue;
 }
 
-VALUE
+static VALUE
 rb_io_close_read(io)
     VALUE io;
 {
diff --git a/lex.c b/lex.c
index a5fb82ebc9..7704876e6f 100644
--- a/lex.c
+++ b/lex.c
@@ -65,6 +65,7 @@ hash (str, len)
   return hval + asso_values[(unsigned char)str[len - 1]];
 }
 
+static
 #ifdef __GNUC__
 __inline
 #endif
diff --git a/ruby.c b/ruby.c
index 757b6ae477..fcbee4c46e 100644
--- a/ruby.c
+++ b/ruby.c
@@ -284,8 +284,8 @@ ruby_init_loadpath()
 struct req_list {
     char *name;
     struct req_list *next;
-} req_list_head;
-struct req_list *req_list_last = &req_list_head;
+};
+static struct req_list req_list_head, *req_list_last = &req_list_head;
 
 static void
 add_modules(mod)
@@ -303,7 +303,7 @@ add_modules(mod)
 
 extern void Init_ext _((void));
 
-void
+static void
 require_libraries()
 {
     extern NODE *ruby_eval_tree;
diff --git a/ruby.h b/ruby.h
index a923521094..82f215b240 100644
--- a/ruby.h
+++ b/ruby.h
@@ -542,6 +542,8 @@ EXTERN VALUE rb_eNameError;
 EXTERN VALUE rb_eSyntaxError;
 EXTERN VALUE rb_eLoadError;
 
+EXTERN VALUE rb_defout, rb_stdin, rb_stdout, rb_stderr, ruby_errinfo;
+
 static inline VALUE
 #if defined(__cplusplus)
 rb_class_of(VALUE obj)
diff --git a/rubyio.h b/rubyio.h
index 00d55baea1..03dac57437 100644
--- a/rubyio.h
+++ b/rubyio.h
@@ -10,8 +10,8 @@
 
 **********************************************************************/
 
-#ifndef IO_H
-#define IO_H
+#ifndef RUBYIO_H
+#define RUBYIO_H
 
 #include <stdio.h>
 #include <errno.h>
diff --git a/version.h b/version.h
index 31714e51ef..7adb428dc4 100644
--- a/version.h
+++ b/version.h
@@ -1,4 +1,4 @@
 #define RUBY_VERSION "1.6.6"
-#define RUBY_RELEASE_DATE "2001-12-13"
+#define RUBY_RELEASE_DATE "2001-12-17"
 #define RUBY_VERSION_CODE 166
-#define RUBY_RELEASE_CODE 20011213
+#define RUBY_RELEASE_CODE 20011217