Improvement of the rake task compile

* release task depends on compile task
* check the presence of toolchain before running the compile task
* remove superfluoous load of mrbtest.rake

Author: toch

Rakefile

@@ -21,6 +21,10 @@ load "#{mruby_root}/Rakefile"
 
 desc "compile all the binaries"
 task :compile => [:all] do
+  MRuby.each_target do |target|
+    `#{target.cc.command} --version`
+    abort("Command #{target.cc.command} for #{target.name} is missing.") unless $?.success?
+  end
   %W(#{mruby_root}/build/x86_64-pc-linux-gnu/bin/#{APP_NAME} #{mruby_root}/build/i686-pc-linux-gnu/#{APP_NAME}").each do |bin|
     sh "strip --strip-unneeded #{bin}" if File.exist?(bin)
   end

mrblib/mruby-cli/setup.rb

@@ -329,6 +329,11 @@ def rakefile
 
 desc "compile binary"
 task :compile => [:all] do
+
+  MRuby.each_target do |target|
+    `\#{target.cc.command} --version`
+    abort("Command \#{target.cc.command} for \#{target.name} is missing.") unless $?.success?
+  end
   %W(\#{mruby_root}/build/x86_64-pc-linux-gnu/bin/\#{APP_NAME} \#{mruby_root}/build/i686-pc-linux-gnu/\#{APP_NAME}").each do |bin|
     sh "strip --strip-unneeded \#{bin}" if File.exist?(bin)
   end