diff --git a/ChangeLog b/ChangeLog
index 6cd2eb3303..345d8e3fa4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Feb 12 20:31:43 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/mkmf.rb (create_tmpsrc): cpp32 of Borland C++ ignores #error
+	  directives in DOS line-ending files at all.
+
 Thu Feb 12 15:23:20 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (rparen): ignore preceding newlines to right parentheses.
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index ece0c3a602..f9fe4608a3 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -216,7 +216,7 @@ end
 def create_tmpsrc(src)
   src = yield(src) if block_given?
   src = src.sub(/[^\n]\z/, "\\&\n")
-  open(CONFTEST_C, "w") do |cfile|
+  open(CONFTEST_C, "wb") do |cfile|
     cfile.print src
   end
   src