Index: ext/rubycocoa/extconf.rb.in
===================================================================
--- ext/rubycocoa/extconf.rb.in	(revision 2219)
+++ ext/rubycocoa/extconf.rb.in	(working copy)
@@ -21,3 +21,13 @@
 create_makefile('rubycocoa')
 command "mv -f Makefile Makefile.bak"
 command "sed -e 's/-no-cpp-precomp//' -e 's/-no-precomp//' Makefile.bak > Makefile"
+
+# if `make' is not MacOSX's make, make do not know about ".m"
+File.open('Makefile', 'a') do |f|
+  f.write <<EOS
+
+.m.o:
+	$(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) -c $<
+
+EOS
+end