[libstdc++] Partial implementation of DR 60.

[Benjamin Kosnik]

>2003-04-23  Phil Edwards  <pme@gcc.gnu.org>
>
>	* docs/html/ext/howto.html ('LWG Issues'):  Add issue 60, partial
>	implementation only.
>	* include/bits/istream.tcc (putback, unget, sync, tellg, seekg):
>	Comment and change to comply with DR 60 and the effect on gcount().
>	* include/std/std_istream.h:  Update comments.
>	* testsuite/27_io/basic_istream/putback/char/1.cc (test01):  Add
>	comments about reasons for tests.  Test sync() against gcount().
>	* testsuite/27_io/basic_istream/seekg/char/2.cc:  New file, test
>	for effect on gcount().
>	* testsuite/27_io/basic_istream/tellg/char/2.cc:  New file, test
>	for effect on gcount().

looks great, thanks!