diff --git a/ChangeLog b/ChangeLog
index 92ebac53e0..b8229f1590 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Mon Jan 14 22:48:16 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* re.c (rb_char_to_option_kcode): use rb_enc_find_index() instead
+	  of using fixed index value.
+
+	* enc/Makefile.in (encsrcdir): make US-ASCII built-in.
+
 Mon Jan 14 22:25:02 2008  WATANABE Hirofumi  <eban@ruby-lang.org>
 
 	* golf_prelude.rb: Shorter method name completion.  Same method
diff --git a/enc/Makefile.in b/enc/Makefile.in
index f33a75d3d2..a1f9142a16 100644
--- a/enc/Makefile.in
+++ b/enc/Makefile.in
@@ -14,7 +14,7 @@ TRANSSODIR = $(ENCSODIR)/trans
 DLEXT = @DLEXT@
 OBJEXT = @OBJEXT@
 
-BUILTIN_ENCS	= ascii.c \
+BUILTIN_ENCS	= ascii.c us_ascii.c\
 		  unicode.c utf8.c
 
 RUBY_SO_NAME = @RUBY_SO_NAME@
diff --git a/encoding.c b/encoding.c
index 01677d1b92..4e3a02f173 100644
--- a/encoding.c
+++ b/encoding.c
@@ -304,9 +304,12 @@ rb_enc_alias(const char *alias, const char *orig)
 enum {
     ENCINDEX_ASCII,
     ENCINDEX_UTF8,
+    ENCINDEX_US_ASCII,
     ENCINDEX_BUILTIN_MAX
 };
 
+extern rb_encoding OnigEncodingUS_ASCII;
+
 void
 rb_enc_init(void)
 {
@@ -314,6 +317,7 @@ rb_enc_init(void)
 #define ENC_REGISTER(enc) enc_register_at(ENCINDEX_##enc, rb_enc_name(ONIG_ENCODING_##enc), ONIG_ENCODING_##enc)
     ENC_REGISTER(ASCII);
     ENC_REGISTER(UTF8);
+    enc_register_at(ENCINDEX_US_ASCII, rb_enc_name(&OnigEncodingUS_ASCII), &OnigEncodingUS_ASCII);
 #undef ENC_REGISTER
 }
 
diff --git a/re.c b/re.c
index 76857dd86a..3f898d7121 100644
--- a/re.c
+++ b/re.c
@@ -142,12 +142,6 @@ rb_memsearch(const void *x0, long m, const void *y0, long n)
 #define ARG_ENCODING_FIXED    16
 #define ARG_ENCODING_NONE     32
 
-#define ARG_KCODE_NONE	      0
-#define ARG_KCODE_EUC 	      1
-#define ARG_KCODE_SJIS	      2
-#define ARG_KCODE_UTF8	      3
-#define ARG_KCODE_MASK	      3
-
 static int
 char_to_option(int c)
 {
@@ -191,13 +185,13 @@ rb_char_to_option_kcode(int c, int *option, int *kcode)
         *kcode = -1;
         return (*option = ARG_ENCODING_NONE);
       case 'e':
-	*kcode = ARG_KCODE_EUC;
+	*kcode = rb_enc_find_index("EUC-JP");
 	break;
       case 's':
-	*kcode = ARG_KCODE_SJIS;
+	*kcode = rb_enc_find_index("Shitf_JIS");
 	break;
       case 'u':
-	*kcode = ARG_KCODE_UTF8;
+	*kcode = rb_enc_find_index("UTF-8");
 	break;
       default:
 	*kcode = -1;
diff --git a/rubytest.rb b/rubytest.rb
index eecc588256..6c3939a0ac 100755
--- a/rubytest.rb
+++ b/rubytest.rb
@@ -37,7 +37,7 @@ $stderr.reopen($stdout)
 error = ''
 
 srcdir = File.dirname(__FILE__)
-`#{ruby} -I#{srcdir} -I#{srcdir}/lib #{srcdir}/sample/test.rb`.each_line do |line|
+`#{ruby} -I.ext/#{RUBY_PLATFORM} -I#{srcdir}/lib #{srcdir}/sample/test.rb`.each_line do |line|
   if line =~ /^end of test/
     print "\ntest succeeded\n"
     exit true