fiddle: win32/libffi-config.rb

* ext/fiddle/win32/libffi-config.rb: generate necessary files to
  build on mswin.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48957 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/fiddle/win32/libffi-config.rb

@@ -0,0 +1,47 @@
+#!/usr/bin/ruby
+require 'fileutils'
+
+basedir = File.dirname(__FILE__)
+conf = {}
+enable = {}
+until ARGV.empty?
+  arg = ARGV.shift
+  case arg
+  when '-C'
+    # ignore
+  when /\A--srcdir=(.*)/
+    conf['SRCDIR'] = srcdir = $1
+  when /\A(CC|CFLAGS|CXX|CXXFLAGS|LD|LDFLAGS)=(.*)/
+    conf[$1] = $2
+  when /\A--host=(.*)/
+    host = $1
+  when /\A--enable-([^=]+)(?:=(.*))?/
+    enable[$1] = $2 || true
+  when /\A--disable-([^=]+)/
+    enable[$1] = false
+  end
+end
+
+IO.foreach("#{srcdir}/configure.ac") do |line|
+  if /^AC_INIT\((.*)\)/ =~ line
+    version = $1.split(/,\s*/)[1]
+    version.gsub!(/\A\[|\]\z/, '')
+    conf['VERSION'] = version
+    break
+  end
+end
+
+builddir = srcdir == "." ? enable['builddir'] : "."
+conf['TARGET'] = /^x64/ =~ host ? "X86_WIN64" : "X86_WIN32"
+
+FileUtils.mkdir_p([builddir, "#{builddir}/include", "#{builddir}/src/x86"])
+FileUtils.cp("#{basedir}/fficonfig.h", ".", preserve: true)
+
+hdr = IO.binread("#{srcdir}/include/ffi.h.in")
+hdr.gsub!(/@(\w+)@/) {conf[$1] || $&}
+hdr.gsub!(/^(#if\s+)@\w+@/, '\10')
+IO.binwrite("#{builddir}/include/ffi.h", hdr)
+
+mk = IO.binread("#{basedir}/libffi.mk.tmpl")
+mk.gsub!(/@(\w+)@/) {conf[$1] || $&}
+IO.binwrite("Makefile", mk)