[v3 PATCH] Implement C++17 string searchers.

[Ville Voutilainen <ville dot voutilainen at gmail dot com>]

The first patch just transforms the TS version into an std one, the second
patch makes it conform by implementing P0253R1. I haven't added
any tests for the pair-seconds of the new api, and I noticed that we
might want to go through our make_pairs and make_tuples and qualify
them throughout the library, where applicable. Such things can be
added with subsequent patches.

2016-09-12  Ville Voutilainen  <ville.voutilainen@gmail.com>

    Implement C++17 string searchers.
    * include/std/functional: (unordered_map, vector): New includes
    in C++17 mode.
    (array, bits/stl_algo.h): Likewise.
    (default_searcher, __boyer_moore_map_base): New.
    (__boyer_moore_array_base, __is_std_equal_to): Likewise.
    (__boyer_moore_base_t, boyer_moore_searcher): Likewise.
    (boyer_moore_horspool_searcher, make_default_searcher): Likewise.
    (make_boyer_moore_searcher): Likewise.
    (make_boyer_moore_horspool_searcher): Likewise.
    * testsuite/20_util/function_objects/searchers.cc: New.


2016-09-12  Ville Voutilainen  <ville.voutilainen@gmail.com>

    Implement P0253R1, Fixing a design mistake in the searchers
    interface in Library Fundamentals.
    * include/std/functional: (utility): New include in C++17 mode.
    (default_searcher): Use a pair as return type, adjust the definition.
    (boyer_moore_searcher): Likewise.
    (boyer_moore_horspool_searcher): Likewise.
    * testsuite/20_util/function_objects/searchers.cc: Adjust.

Attachment: searchers.diff
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Attachment: searchers2.diff
Description: Text document