Very basic cli to compile ruby files

Off course this is basically a cross compiler and the files
have to be transferred to an arm machine (and fixed as per note)
close #22

lib/rubyx/rubyxc.rb

@@ -0,0 +1,33 @@
+require "thor"
+require "rubyx"
+
+class RubyXC < Thor
+  desc "compile FILE" , "Compile given FILE to binary"
+  long_desc <<-LONGDESC
+      Very basic cli to compile ruby programs.
+      Currently only compile command supported without option.
+
+      Output will be elf object file of the same name, with .o, in root directory.
+
+      Note: Because of Bug #13, you need to run "ld -N file.o" on the file, before
+      executing it. This can be done on a mac by installing a cross linker
+      (brew install arm-linux-gnueabihf-binutils), or on the target arm machine.
+    LONGDESC
+
+  def compile(file)
+    begin
+      ruby = File.read(file)
+    rescue
+      fail MalformattedArgumentError , "No such file #{file}"
+    end
+    puts "compiling #{file}"
+
+    linker = ::RubyX::RubyXCompiler.new.ruby_to_binary( ruby , :arm )
+    writer = Elf::ObjectWriter.new(linker)
+
+    outfile = file.split("/").last.gsub(".rb" , ".o")
+    writer.save outfile
+
+    return outfile
+  end
+end