re PR libstdc++/57808 (operators == and != for regex_token_iterator need to be const)

2013-07-04  Ray Chason  <chasonr@newsguy.com>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/57808
	* include/bits/regex.h (regex_token_iterator<>::operator==,
	regex_token_iterator<>::operator!=, regex_token_iterator<>::operator*,
	regex_token_iterator<>::operator->): Declare const.

Co-Authored-By: Paolo Carlini <paolo.carlini@oracle.com>

From-SVN: r200662