Use block variable instead of global

```ruby
require 'benchmark/ips'

Benchmark.ips do |x|
  x.report("$&") {
    "foo".sub(/f/) { $&.upcase }
  }
  x.report("block var") {
    "foo".sub(/f/) {|match| match.upcase }
  }
end

```

```
Calculating -------------------------------------
                  $&    48.658k i/100ms
           block var    49.666k i/100ms
-------------------------------------------------
                  $&    873.156k (± 9.3%) i/s -      4.331M
           block var    969.744k (± 9.2%) i/s -      4.818M
```

It's faster, and gets rid of a few "magic" global variables

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/profile b/tools/profile
index eb7fc7792b..191e73b3dd 100755
--- a/tools/profile
+++ b/tools/profile
@@ -117,9 +117,9 @@ rescue LoadError
     def camelize(uppercase_first_letter = true)
       string = self
       if uppercase_first_letter
-        string = string.sub(/^[a-z\d]*/) { $&.capitalize }
+        string = string.sub(/^[a-z\d]*/) { |match| match.capitalize }
       else
-        string = string.sub(/^(?:(?=\b|[A-Z_])|\w)/) { $&.downcase }
+        string = string.sub(/^(?:(?=\b|[A-Z_])|\w)/) { |match| match.downcase }
       end
       string.gsub(/(?:_|(\/))([a-z\d]*)/) { "#{$1}#{$2.capitalize}" }.gsub('/', '::')
     end