PR libstdc++/65927 Fix -Wunused-but-set-parameter warning

	PR libstdc++/65927
	* include/bits/locale_facets_nonio.h (__timepunct::_M_am_pm_format):
	Remove statement with no effect.

From-SVN: r255278

libstdc++-v3/ChangeLog

+2017-11-30  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/65927
+	* include/bits/locale_facets_nonio.h (__timepunct::_M_am_pm_format):
+	Remove statement with no effect.
+
 2017-11-30  Glen Joseph Fernandes  <glenjofe@gmail.com>
 
 	* include/bits/ptr_traits.h (__to_address, to_address): Move static

libstdc++-v3/include/bits/locale_facets_nonio.h

@@ -236,9 +236,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	__dt[1] = _M_data->_M_date_time_era_format;
       }
 
+#if !_GLIBCXX_INLINE_VERSION
       void
-      _M_am_pm_format(const _CharT* __ampm) const
-      { __ampm = _M_data->_M_am_pm_format; }
+      _M_am_pm_format(const _CharT*) const
+      { /* Kept for ABI compatibility, see PR65927 */ }
+#endif
 
       void
       _M_am_pm(const _CharT** __ampm) const