diff --git a/ChangeLog b/ChangeLog
index cac282c0b1..56cd2b365a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Nov  2 20:02:22 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/mkmf.rb (MakeMakefile#timestamp_file): use .-. instead of !, a
+	  special character of NMAKE and BSD make.  [Bug #7265]
+
 Fri Nov  2 17:55:39 2012  Shota Fukumori  <sorah@tubusu.net>
 
 	* lib/test/unit.rb (_run_parallel): Delete status line before showing
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index 84d736dac0..f67e4d0089 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -1859,7 +1859,7 @@ preload = #{defined?($preload) && $preload ? $preload.join(' ') : ''}
   end
 
   def timestamp_file(name)
-    name = name.gsub(/(\$[({]|[})])|(\/+)|[^-.\w]+/) {$1 ? "@" : $2 ? "!" : "_"}
+    name = name.gsub(/(\$[({]|[})])|(\/+)|[^-.\w]+/) {$1 ? "@" : $2 ? ".-." : "_"}
     "./.#{name}.time"
   end
   # :startdoc: