Build process updated:

You have to specify `TARGET` to specify a configuration, e.g.

```
rake TARGET=host-debug all test
```

When you port `mruby` to a new configuration:
1. copy an existing configuration under `target` directory
2. modify the new configuration file
3. build using the new configuration
4. send PR if you please

1 files changed, 106 insertions, 0 deletions

diff --git a/target/IntelGalileo.rb b/target/IntelGalileo.rb
new file mode 100644
index 000000000..42f39c456
--- /dev/null
+++ b/target/IntelGalileo.rb
@@ -0,0 +1,106 @@
+MRuby::Build.new do |conf|
+
+  # Gets set by the VS command prompts.
+  if ENV['VisualStudioVersion'] || ENV['VSINSTALLDIR']
+    toolchain :visualcpp
+  else
+    toolchain :gcc
+  end
+
+  enable_debug
+
+  # include the default GEMs
+  conf.gembox 'default'
+
+end
+
+
+# Cross Compiling configuration for Intel Galileo on Arduino environment
+# http://arduino.cc/en/ArduinoCertified/IntelGalileo
+#
+# Requires Arduino IDE for Intel Galileo
+MRuby::CrossBuild.new("Galileo") do |conf|
+  toolchain :gcc
+
+  # Mac OS X
+  # Assume you renamed Arduino.app to Arduino_Galileo.app
+  GALILEO_ARDUINO_PATH = '/Applications/Arduino_Galileo.app/Contents/Resources/Java'
+  # GNU Linux
+  #ARDUINO_GALILEO_PATH = '/opt/arduino'
+
+  GALILEO_BIN_PATH = "#{GALILEO_ARDUINO_PATH}/hardware/tools/x86/i386-pokysdk-darwin/usr/bin/i586-poky-linux-uclibc"
+  GALILEO_SYSROOT =  "#{GALILEO_ARDUINO_PATH}/hardware/tools/x86/i586-poky-linux-uclibc"
+  GALILEO_X86_PATH = "#{GALILEO_ARDUINO_PATH}/hardware/arduino/x86"
+
+
+  conf.cc do |cc|
+    cc.command = "#{GALILEO_BIN_PATH}/i586-poky-linux-uclibc-gcc"
+    cc.include_paths << ["#{GALILEO_X86_PATH}/cores/arduino", "#{GALILEO_X86_PATH}/variants/galileo_fab_d"]
+    cc.flags = %w(-m32 -march=i586 -c -g -Os -w
+              -ffunction-sections -fdata-sections -MMD -DARDUINO=153)
+    cc.flags << "--sysroot=#{GALILEO_SYSROOT}"
+    cc.compile_options = %Q[%{flags} -o "%{outfile}" -c "%{infile}"]
+  end
+
+  conf.cxx do |cxx|
+    cxx.command = "#{GALILEO_BIN_PATH}/i586-poky-linux-uclibc-g++"
+    cxx.include_paths = conf.cc.include_paths.dup
+    cxx.include_paths << "#{GALILEO_ARDUINO_PATH}/hardware/tools/x86/i586-poky-linux-uclibc/usr/include/c++"
+    cxx.include_paths << "#{GALILEO_ARDUINO_PATH}/hardware/tools/x86/i586-poky-linux-uclibc/usr/include/c++/i586-poky-linux-uclibc"
+    cxx.flags = conf.cc.flags.dup
+    cxx.defines = conf.cc.defines.dup
+    cxx.compile_options = conf.cc.compile_options.dup
+  end
+
+  conf.archiver do |archiver|
+    archiver.command = "#{GALILEO_BIN_PATH}/i586-poky-linux-uclibc-ar"
+    archiver.archive_options = 'rcs "%{outfile}" %{objs}'
+  end
+
+  conf.linker do |linker|
+    linker.command = "#{GALILEO_BIN_PATH}/i586-poky-linux-uclibc-g++"
+    linker.flags = %w(-m32 -march=i586)
+    linker.flags << "--sysroot=#{GALILEO_SYSROOT}"
+    linker.flags << %w(-Os -Wl,--gc-sections)
+    linker.libraries = %w(m pthread)
+  end
+
+  #no executables
+  conf.bins = []
+
+  #do not build executable test
+  conf.build_mrbtest_lib_only
+
+  #official mrbgems
+  conf.gem :core => "mruby-sprintf"
+  conf.gem :core => "mruby-print"
+  conf.gem :core => "mruby-math"
+  conf.gem :core => "mruby-time"
+  conf.gem :core => "mruby-struct"
+  conf.gem :core => "mruby-enum-ext"
+  conf.gem :core => "mruby-string-ext"
+  conf.gem :core => "mruby-numeric-ext"
+  conf.gem :core => "mruby-array-ext"
+  conf.gem :core => "mruby-hash-ext"
+  conf.gem :core => "mruby-range-ext"
+  conf.gem :core => "mruby-proc-ext"
+  conf.gem :core => "mruby-symbol-ext"
+  conf.gem :core => "mruby-random"
+  conf.gem :core => "mruby-object-ext"
+  conf.gem :core => "mruby-objectspace"
+  conf.gem :core => "mruby-fiber"
+  conf.gem :core => "mruby-toplevel-ext"
+
+  #lightweigh regular expression
+  conf.gem :github => "masamitsu-murase/mruby-hs-regexp", :branch => "master"
+
+  #Arduino API
+  #conf.gem :github =>"kyab/mruby-arduino", :branch => "master" do |g|
+  #  g.cxx.include_paths << "#{GALILEO_X86_PATH}/libraries/Wire"
+  #  g.cxx.include_paths << "#{GALILEO_X86_PATH}/libraries/Servo"
+
+    #enable unsupported Servo class
+  #  g.cxx.defines << "MRUBY_ARDUINO_GALILEO_ENABLE_SERVO"
+  #end
+
+end