diff --git a/ChangeLog b/ChangeLog
index f9a67710f9..38d2b77ba3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+Sat Nov 10 18:10:07 2007  Tanaka Akira  <akr@fsij.org>
+
+	* gem_prelude.rb: new file for gem libraries.  currently empty.
+
+	* common.mk: generate ext_prelude.c by prelude.rb and gem_prelude.rb.
+	  ruby (not miniruby) is linked with ext_prelude.o instead of prelude.o. 
+	* inits.c (rb_call_inits): don't call Init_prelude.
+
+	* ruby.c: support --disable-gems option.
+	  (ruby_init_gems): new function to define Gem::Enable and
+	  invoke Init_prelude.
+	  (process_options): call ruby_init_gems just after
+	  ruby_init_loadpath.
+
+	* tool/compile_prelude.rb: support multiple files.
+
 Sat Nov 10 17:27:55 2007  Shugo Maeda  <shugo@ruby-lang.org>
 
 	* thread.c (call_trace_proc): don't call ID2SYM() for ID_ALLOCATOR
diff --git a/Makefile.in b/Makefile.in
index 2c5b4b23a9..99f4a3929d 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -50,7 +50,7 @@ LDSHARED = @LIBRUBY_LDSHARED@
 DLDFLAGS = @LIBRUBY_DLDFLAGS@ $(EXTLDFLAGS) @ARCH_FLAG@
 SOLIBS = @SOLIBS@
 MAINLIBS = @MAINLIBS@
-MINIOBJS = @MINIOBJS@
+MINIOBJS = @MINIOBJS@ prelude.$(OBJEXT)
 
 RUBY_INSTALL_NAME=@RUBY_INSTALL_NAME@
 RUBY_SO_NAME=@RUBY_SO_NAME@
diff --git a/common.mk b/common.mk
index 39669487bc..177a058253 100644
--- a/common.mk
+++ b/common.mk
@@ -15,7 +15,7 @@ RDOCOUT       = $(EXTOUT)/rdoc
 
 DMYEXT	      = dmyext.$(OBJEXT)
 MAINOBJ	      = main.$(OBJEXT)
-EXTOBJS	      = 
+EXTOBJS	      = ext_prelude.$(OBJEXT)
 DLDOBJS	      = $(DMYEXT)
 
 ENCOBJS       = ascii.$(OBJEXT) \
@@ -78,7 +78,6 @@ OBJS	      = array.$(OBJEXT) \
 		thread.$(OBJEXT) \
 		cont.$(OBJEXT) \
 		id.$(OBJEXT) \
-		prelude.$(OBJEXT) \
 		$(ENCOBJS) \
 		$(MISSING)
 
@@ -586,6 +585,7 @@ blockinlining.$(OBJEXT): {$(VPATH)}blockinlining.c \
         {$(VPATH)}thread_$(THREAD_MODEL).h
 id.$(OBJEXT): {$(VPATH)}id.c {$(VPATH)}ruby.h
 prelude.$(OBJEXT): {$(VPATH)}prelude.c {$(VPATH)}ruby.h {$(VPATH)}vm_core.h
+ext_prelude.$(OBJEXT): {$(VPATH)}ext_prelude.c {$(VPATH)}ruby.h {$(VPATH)}vm_core.h
 
 ascii.$(OBJEXT): {$(VPATH)}ascii.c {$(VPATH)}regenc.h \
   {$(VPATH)}oniguruma.h {$(VPATH)}config.h {$(VPATH)}defines.h
@@ -631,6 +631,9 @@ node_name.inc: {$(VPATH)}node.h
 prelude.c: $(srcdir)/tool/compile_prelude.rb $(srcdir)/prelude.rb
 	$(BASERUBY) $(srcdir)/tool/compile_prelude.rb $(srcdir)/prelude.rb $@
 
+ext_prelude.c: $(srcdir)/tool/compile_prelude.rb $(srcdir)/prelude.rb $(srcdir)/gem_prelude.rb $(RBCONFIG)
+	$(MINIRUBY) -I$(srcdir) -rrbconfig $(srcdir)/tool/compile_prelude.rb $(srcdir)/prelude.rb $(srcdir)/gem_prelude.rb $@
+
 prereq: incs {$(VPATH)}prelude.c
 
 docs:
diff --git a/gem_prelude.rb b/gem_prelude.rb
new file mode 100644
index 0000000000..7340efcaaf
--- /dev/null
+++ b/gem_prelude.rb
@@ -0,0 +1,10 @@
+# empty gem_prelude.rb
+#
+# p Gem::Enable
+# p RbConfig::CONFIG["arch"]
+# p RbConfig::CONFIG["bindir"]
+# p RbConfig::CONFIG["datadir"]
+# p RbConfig::CONFIG["sitedir"]
+# p RbConfig::CONFIG["sitelibdir"]
+# p RbConfig::CONFIG["EXEEXT"]
+# p RbConfig::CONFIG["RUBY_SO_NAME"]
diff --git a/inits.c b/inits.c
index f6e4502dfb..3006bf6098 100644
--- a/inits.c
+++ b/inits.c
@@ -51,7 +51,6 @@ void Init_VM(void);
 void Init_Thread(void);
 void Init_Cont(void);
 void Init_top_self(void);
-void Init_prelude(void);
 void Init_Encoding(void);
 
 void
@@ -97,5 +96,4 @@ rb_call_inits()
     Init_Thread();
     Init_Cont();
     Init_version();
-    Init_prelude();
 }
diff --git a/ruby.c b/ruby.c
index 6dc411eaa0..4285247005 100644
--- a/ruby.c
+++ b/ruby.c
@@ -75,6 +75,7 @@ struct cmdline_options {
     int usage;
     int version;
     int copyright;
+    int disable_gems;
     int verbose;
     int yydebug;
     char *script;
@@ -121,6 +122,7 @@ usage(const char *name)
 	"-w              turn warnings on for your script",
 	"-W[level]       set warning level; 0=silence, 1=medium, 2=verbose (default)",
 	"-x[directory]   strip off text before #!ruby line and perhaps cd to directory",
+	"--disable_gems  disable gem libraries",
 	"--copyright     print the copyright",
 	"--version       print the version",
 	NULL
@@ -813,6 +815,8 @@ proc_options(int argc, char **argv, struct cmdline_options *opt)
 		ruby_debug = Qtrue;
                 ruby_verbose = Qtrue;
             }
+            else if (strcmp("disable-gems", s) == 0)
+		opt->disable_gems = 1;
 	    else if (strcmp("encoding", s) == 0) {
 		if (!--argc || !(s = *++argv)) {
 		  noencoding:
@@ -873,6 +877,17 @@ proc_options(int argc, char **argv, struct cmdline_options *opt)
     return argc0 - argc;
 }
 
+void Init_prelude(void);
+
+static void
+ruby_init_gems(struct cmdline_options *opt)
+{
+    VALUE gem;
+    gem = rb_define_module("Gem");
+    rb_const_set(gem, rb_intern("Enable"), opt->disable_gems ? Qfalse : Qtrue);
+    Init_prelude();
+}
+
 static VALUE
 process_options(VALUE arg)
 {
@@ -976,6 +991,7 @@ process_options(VALUE arg)
     process_sflag(opt);
 
     ruby_init_loadpath();
+    ruby_init_gems(opt);
     parser = rb_parser_new();
     if (opt->e_script) {
 	if (opt->enc_index >= 0)
diff --git a/tool/compile_prelude.rb b/tool/compile_prelude.rb
index 1012d1fbc2..1f67d4c396 100644
--- a/tool/compile_prelude.rb
+++ b/tool/compile_prelude.rb
@@ -1,33 +1,79 @@
+*preludes, outfile = *ARGV
 
-prelude, outfile = *ARGV
+C_ESC = {
+  "\\" => "\\\\",
+  '"' => '\"',
+  "\n" => '\n',
+}
 
-lines = File.readlines(prelude).map{|line|
-  line.dump
+0x00.upto(0x1f) {|ch| C_ESC[[ch].pack("C")] ||= "\\x%02x" % ch }
+0x7f.upto(0xff) {|ch| C_ESC[[ch].pack("C")] = "\\x%02x" % ch }
+C_ESC_PAT = Regexp.union(*C_ESC.keys)
+
+def c_esc(str)
+  '"' + str.gsub(C_ESC_PAT) { C_ESC[$&] } + '"'
+end
+
+lines_list = preludes.map {|prelude|
+  lines = []
+  File.readlines(prelude).each {|line|
+    line.gsub!(/RbConfig::CONFIG\["(\w+)"\]/) {
+      require 'rbconfig'
+      if RbConfig::CONFIG.has_key? $1
+        c_esc(RbConfig::CONFIG[$1])
+      else
+        $&
+      end
+    }
+    lines << c_esc(line)
+  }
+  lines
 }
 
 open(outfile, 'w'){|f|
-  f.puts <<EOS__, <<'EOS__'
+  f.puts <<'EOS__'
 
 #include "ruby/ruby.h"
 #include "vm_core.h"
 
-static const char prelude_name[] = "#{File.basename(prelude)}";
-static const char prelude_code[] =
+EOS__
+
+  preludes.zip(lines_list).each_with_index {|(prelude, lines), i|
+    f.puts <<EOS__
+static const char prelude_name#{i}[] = "#{File.basename(prelude)}";
+static const char prelude_code#{i}[] =
 #{lines.join("\n")}
 ;
 EOS__
+  }
+  f.puts <<'EOS__'
 
 void
 Init_prelude(void)
 {
+EOS__
+  preludes.length.times {|i|
+    f.puts <<EOS__
   rb_iseq_eval(rb_iseq_compile(
-    rb_str_new(prelude_code, sizeof(prelude_code) - 1),
-    rb_str_new(prelude_name, sizeof(prelude_name) - 1),
+    rb_str_new(prelude_code#{i}, sizeof(prelude_code#{i}) - 1),
+    rb_str_new(prelude_name#{i}, sizeof(prelude_name#{i}) - 1),
     INT2FIX(1)));
 
+EOS__
+  }
+    f.puts <<EOS__
 #if 0
-    printf("%s\n", prelude_code);
+EOS__
+  preludes.length.times {|i|
+    f.puts <<EOS__
+    puts(prelude_code#{i});
+EOS__
+  }
+    f.puts <<EOS__
 #endif
+EOS__
+
+  f.puts <<'EOS__'
 }
 EOS__
 }