--- ./test/fiddle/helper.rb.origine	2015-12-16 06:07:31 +0100
+++ ./test/fiddle/helper.rb	2016-10-27 11:11:56 +0200
@@ -63,10 +63,19 @@
   pwd=Dir.pwd
   libc_so = libm_so = "#{pwd}/libaixdltest.so"
   unless File.exist? libc_so
+    
     cobjs=%w!strcpy.o!
     mobjs=%w!floats.o sin.o!
     funcs=%w!sin sinf strcpy strncpy!
     expfile='dltest.exp'
+
+    case [0].pack('L!').size
+    when 8
+      # 64-bit ruby
+      cobjs=%w!strcpy_64.o!
+      mobjs=%w!floats_64.o sin_64.o!
+    end
+    
     require 'tmpdir'
     Dir.mktmpdir do |dir|
       begin