* ext/fiddle/*: Adding fiddle library to wrap libffi

* test/fiddle/*: testing fiddle extension
* ext/dl/lib/dl.rb: Requiring fiddle if it is available
* ext/dl/lib/dl/callback.rb: using Fiddle if it is available
* ext/dl/lib/dl/func.rb: ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27640 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/fiddle/helper.rb

@@ -0,0 +1,71 @@
+require 'minitest/autorun'
+require 'dl'
+require 'fiddle'
+
+# FIXME: this is stolen from DL and needs to be refactored.
+require_relative '../ruby/envutil'
+
+libc_so = libm_so = nil
+
+case RUBY_PLATFORM
+when /cygwin/
+  libc_so = "cygwin1.dll"
+  libm_so = "cygwin1.dll"
+when /x86_64-linux/
+  libc_so = "/lib64/libc.so.6"
+  libm_so = "/lib64/libm.so.6"
+when /linux/
+  libdir = '/lib'
+  case [0].pack('L!').size
+  when 4
+    # 32-bit ruby
+    libdir = '/lib32' if File.directory? '/lib32'
+  when 8
+    # 64-bit ruby
+    libdir = '/lib64' if File.directory? '/lib64'
+  end
+  libc_so = File.join(libdir, "libc.so.6")
+  libm_so = File.join(libdir, "libm.so.6")
+when /mingw/, /mswin/
+  require "rbconfig"
+  libc_so = libm_so = RbConfig::CONFIG["RUBY_SO_NAME"].split(/-/, 2)[0] + ".dll"
+when /darwin/
+  libc_so = "/usr/lib/libc.dylib"
+  libm_so = "/usr/lib/libm.dylib"
+when /kfreebsd/
+  libc_so = "/lib/libc.so.0.1"
+  libm_so = "/lib/libm.so.1"
+when /bsd|dragonfly/
+  libc_so = "/usr/lib/libc.so"
+  libm_so = "/usr/lib/libm.so"
+else
+  libc_so = ARGV[0] if ARGV[0] && ARGV[0][0] == ?/
+  libm_so = ARGV[1] if ARGV[1] && ARGV[1][0] == ?/
+  if( !(libc_so && libm_so) )
+    $stderr.puts("libc and libm not found: #{$0} <libc> <libm>")
+  end
+end
+
+libc_so = nil if !libc_so || (libc_so[0] == ?/ && !File.file?(libc_so))
+libm_so = nil if !libm_so || (libm_so[0] == ?/ && !File.file?(libm_so))
+
+if !libc_so || !libm_so
+  ruby = EnvUtil.rubybin
+  ldd = `ldd #{ruby}`
+  #puts ldd
+  libc_so = $& if !libc_so && %r{/\S*/libc\.so\S*} =~ ldd
+  libm_so = $& if !libm_so && %r{/\S*/libm\.so\S*} =~ ldd
+  #p [libc_so, libm_so]
+end
+
+Fiddle::LIBC_SO = libc_so
+Fiddle::LIBM_SO = libm_so
+
+module Fiddle
+  class TestCase < MiniTest::Unit::TestCase
+    def setup
+      @libc = DL.dlopen(LIBC_SO)
+      @libm = DL.dlopen(LIBM_SO)
+    end
+  end
+end