diff --git a/ChangeLog b/ChangeLog
index 29df133567..50f81e87e0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Mar 29 20:21:58 2002  Nobuyoshi Nakada  <nobu.nakada@nifty.ne.jp>
+
+	* lib/mkmf.rb (create_makefile): default FLAGS to empty strings.
+
 Fri Mar 29 16:36:52 2002  Nobuyoshi Nakada  <nobu.nakada@nifty.ne.jp>
 
 	* lib/mkmf.rb (arg_config): should use Shellwords::shellwords like
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index f0a846a25d..1a6a318071 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -617,9 +617,9 @@ $defs = []
 
 $make = with_config("make-prog", ENV["MAKE"] || "make")
 
-$CFLAGS = with_config("cflags", arg_config("CFLAGS"))
-$CPPFLAGS = with_config("cppflags", arg_config("CPPFLAGS"))
-$LDFLAGS = with_config("ldflags", arg_config("LDFLAGS"))
+$CFLAGS = with_config("cflags", arg_config("CFLAGS", ""))
+$CPPFLAGS = with_config("cppflags", arg_config("CPPFLAGS", ""))
+$LDFLAGS = with_config("ldflags", arg_config("LDFLAGS", ""))
 $LIBPATH = []
 
 dir_config("opt")