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, 1 insertions, 5 deletions

diff --git a/tasks/benchmark.rake b/tasks/benchmark.rake
index 6352f5c17..661fd2ada 100644
--- a/tasks/benchmark.rake
+++ b/tasks/benchmark.rake
@@ -9,11 +9,7 @@ def bm_files
 end
 
 def build_config_name
-  if ENV['MRUBY_CONFIG']
-    File.basename(ENV['MRUBY_CONFIG'], '.rb').gsub('build_config_', '')
-  else
-    "build"
-  end
+  MRUBY_TARGET
 end
 
 def plot_file