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, 86 insertions, 0 deletions

diff --git a/target/chipKITMax32.rb b/target/chipKITMax32.rb
new file mode 100644
index 000000000..8617d8d10
--- /dev/null
+++ b/target/chipKITMax32.rb
@@ -0,0 +1,86 @@
+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 Digilent chipKIT Max32
+# http://www.digilentinc.com/Products/Detail.cfm?Prod=CHIPKIT-MAX32
+#
+# Requires MPIDE (https://github.com/chipKIT32/chipKIT32-MAX)
+#
+# This configuration is based on @kyab's version
+# http://d.hatena.ne.jp/kyab/20130201
+MRuby::CrossBuild.new("chipKITMax32") do |conf|
+  toolchain :gcc
+
+  # Mac OS X
+  # MPIDE_PATH = '/Applications/Mpide.app/Contents/Resources/Java'
+  # GNU Linux
+  MPIDE_PATH = '/opt/mpide-0023-linux-20120903'
+
+  PIC32_PATH = "#{MPIDE_PATH}/hardware/pic32"
+
+  conf.cc do |cc|
+    cc.command = "#{PIC32_PATH}/compiler/pic32-tools/bin/pic32-gcc"
+    cc.include_paths << ["#{PIC32_PATH}/cores/pic32",
+                        "#{PIC32_PATH}/variants/Max32",
+                        "#{PIC32_PATH}/libraries"]
+    cc.flags = %w(-O2 -mno-smart-io -w -ffunction-sections -fdata-sections -g -mdebugger -Wcast-align
+                -fno-short-double -mprocessor=32MX795F512L -DF_CPU=80000000L -DARDUINO=23 -D_BOARD_MEGA_
+                -DMPIDEVER=0x01000202 -DMPIDE=23)
+    cc.compile_options = %Q[%{flags} -o "%{outfile}" -c "%{infile}"]
+
+    #configuration for low memory environment
+    cc.defines << %w(MRB_HEAP_PAGE_SIZE=64)
+    cc.defines << %w(KHASH_DEFAULT_SIZE=8)
+    cc.defines << %w(MRB_STR_BUF_MIN_SIZE=20)
+    cc.defines << %w(MRB_GC_STRESS)
+    #cc.defines << %w(MRB_DISABLE_STDIO) #if you dont need stdio.
+    #cc.defines << %w(POOL_PAGE_SIZE=1000) #effective only for use with mruby-eval
+  end
+
+  conf.cxx do |cxx|
+    cxx.command = conf.cc.command.dup
+    cxx.include_paths = conf.cc.include_paths.dup
+    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 = "#{PIC32_PATH}/compiler/pic32-tools/bin/pic32-ar"
+    archiver.archive_options = 'rcs "%{outfile}" %{objs}'
+  end
+
+  #no executables
+  conf.bins = []
+
+  #do not build test executable
+  conf.build_mrbtest_lib_only
+
+  #disable C++ exception
+  conf.disable_cxx_exception
+
+  #gems from core
+  conf.gem :core => "mruby-print"
+  conf.gem :core => "mruby-math"
+  conf.gem :core => "mruby-enum-ext"
+
+  #light-weight regular expression
+  conf.gem :github => "masamitsu-murase/mruby-hs-regexp", :branch => "master"
+
+  #Arduino API
+  #conf.gem :github =>"kyab/mruby-arduino", :branch => "master"
+
+end