diff --git a/ChangeLog b/ChangeLog
index f04764cade..deb1cf17b0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Fri Sep  3 01:54:20 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/extmk.rb (extmake): extact target prefix from Makefiles.
+
+	* ext/extmk.rb: already built-in libraries satisfy dependencies.
+	  [ruby-dev:24028]
+
 Wed Sep  1 21:16:50 2004  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
 
 	* ext/tk/lib/tk/spinbox.rb: fix typo
diff --git a/ext/extmk.rb b/ext/extmk.rb
index 7d49f49e39..c41354bf46 100644
--- a/ext/extmk.rb
+++ b/ext/extmk.rb
@@ -103,7 +103,11 @@ def extmake(target)
       else
 	if $static
 	  m = File.read(makefile)
-	  $target = m[/^TARGET[ \s]*=[ \s]*(\S*)/, 1] or $static = nil
+	  if !($target = m[/^TARGET[ \t]*=[ \t]*(\S*)/, 1])
+	    $static = nil
+	  elsif target_prefix = m[/^target_prefix[ \t]*=[ \t]*\/(.*)/, 1]
+	    $target = "#{target_prefix}/#{$target}"
+	  end
 	  /^STATIC_LIB[ \t]*=[ \t]*\S+/ =~ m or $static = nil
 	  $preload = Shellwords.shellwords(m[/^preload[ \t]*=[ \t]*(.*)/, 1] || "")
 	  $DLDFLAGS += " " + (m[/^DLDFLAGS[ \t]*=[ \t]*(.*)/, 1] || "")
@@ -353,9 +357,10 @@ if $extlist.size > 0
   $extinit ||= ""
   $extobjs ||= ""
   list = $extlist.dup
+  built = []
   while e = list.shift
     s,t,i,r = e
-    if r and !r.empty?
+    if r and !(r -= built).empty?
       l = list.size
       if (while l > 0; break true if r.include?(list[l-=1][1]) end)
         list.insert(l + 1, e)
@@ -366,6 +371,7 @@ if $extlist.size > 0
     if File.exist?(f)
       $extinit += "\tinit(Init_#{i}, \"#{t}.so\");\n"
       $extobjs += "ext/#{f} "
+      built << t
     end
   end