Remove needless backtracking

This caused ruby 1.8.7 to have an overflow in the regular expression
matcher as it continually tried to backtrack on uncaptured content.

Fixes #327

Author: drbrain

lib/rdoc/parser/c.rb

@@ -745,10 +745,10 @@ def find_class_comment class_name, class_mod
     elsif @content =~ %r%Document-(?:class|module):\s+#{class_name}\s*?
                          (?:<\s+[:,\w]+)?\n((?>.*?\*/))%xm then
       comment = "/*\n#{$1}"
-    elsif @content =~ %r%.*((?>/\*.*?\*/\s+))
+    elsif @content =~ %r%((?>/\*.*?\*/\s+))
                          ([\w\.\s]+\s* = \s+)?rb_define_(class|module).*?"(#{class_name})"%xm then
       comment = $1
-    elsif @content =~ %r%.*((?>/\*.*?\*/\s+))
+    elsif @content =~ %r%((?>/\*.*?\*/\s+))
                          ([\w\.\s]+\s* = \s+)?rb_define_(class|module)_under.*?"(#{class_name.split('::').last})"%xm then
       comment = $1
     else