extconf.rb in fspath-mac-3.1.1

- old
+ new

@@ -1,5 +1,13 @@
 require 'mkmf'
 
 with_ldflags($LDFLAGS + ' -framework AppKit'){ true }
 
 create_makefile('fspath/mac/ext')
+
+# fix Makefile not containing rule for .m
+makefile = File.read('Makefile')
+if makefile && makefile['.c.o:'] && !makefile['.m.o:']
+  File.open('Makefile', 'w') do |f|
+    f << makefile.sub('.c.o:', '.m.o:')
+  end
+end