diff --git a/ChangeLog b/ChangeLog
index c9cff704c5..3049131729 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,27 @@
+Mon Dec 17 16:52:20 2001  Nobuyoshi Nakada  <nobu.nakada@nifty.ne.jp>
+
+	* intern.h: add prototypes.
+	  rb_gc_enable(), rb_gc_disable(), rb_gc_start(), rb_str_new5()
+	  rb_str_buf_append(), rb_str_buf_cat(), rb_str_buf_cat2(),
+	  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.
+
 Mon Dec 17 15:19:32 2001  Tanaka Akira  <akr@m17n.org>
 
 	* time.c: new method `gmtoff', `gmt_offset' and `utc_offset'.
diff --git a/array.c b/array.c
index b58f484fc0..a7b91756b5 100644
--- a/array.c
+++ b/array.c
@@ -924,7 +924,7 @@ 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 18abc8a6de..d7073c7330 100644
--- a/eval.c
+++ b/eval.c
@@ -699,7 +699,7 @@ 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 0780524a5b..4f7338115f 100644
--- a/intern.h
+++ b/intern.h
@@ -199,6 +199,9 @@ void rb_gc_mark _((VALUE));
 void rb_gc_force_recycle _((VALUE));
 void rb_gc _((void));
 void rb_gc_call_finalizer_at_exit _((void));
+VALUE rb_gc_enable _((void));
+VALUE rb_gc_disable _((void));
+VALUE rb_gc_start _((void));
 /* hash.c */
 VALUE rb_hash _((VALUE));
 VALUE rb_hash_new _((void));
@@ -331,12 +334,17 @@ VALUE rb_str_new _((const char*, long));
 VALUE rb_str_new2 _((const char*));
 VALUE rb_str_new3 _((VALUE));
 VALUE rb_str_new4 _((VALUE));
+VALUE rb_str_new5 _((VALUE, const char *, long));
 VALUE rb_tainted_str_new _((const char*, long));
 VALUE rb_tainted_str_new2 _((const char*));
 VALUE rb_str_buf_new _((long));
 VALUE rb_str_buf_new2 _((const char*));
+VALUE rb_str_buf_append _((VALUE, VALUE));
+VALUE rb_str_buf_cat _((VALUE, const char *, long));
+VALUE rb_str_buf_cat2 _((VALUE, const char *));
 VALUE rb_obj_as_string _((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 0984fdfe02..465b3d0a93 100644
--- a/io.c
+++ b/io.c
@@ -1139,7 +1139,7 @@ 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 67f1337987..979246f047 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 9d0e282d97..f73194bbec 100644
--- a/ruby.c
+++ b/ruby.c
@@ -286,8 +286,8 @@ 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)
@@ -305,7 +305,7 @@ 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 31a147fcc9..e5ff9769e4 100644
--- a/ruby.h
+++ b/ruby.h
@@ -579,6 +579,8 @@ 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 6e63711ee9..fb012045f1 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>