rubinius/rubinius — pull request #1662 by IPGlider (2012-04-11 23:47:57+00:00)
Title: Make String#to_f returns 0.0 for strings with leading underscores

In Ruby 1.9.3

```ruby
1.9.3p125 :001 > "_9".to_f
=> 0.0
```
Before patch in Rubinius in 1.9 mode

```ruby
rubinius-2.0.0dev :001 > "_9".to_f
=> 9.0
```

After patch in Rubinius in 1.9 mode

```ruby
rubinius-2.0.0dev :001 > "_9".to_f
=> 0.0
```