PR c++/69560 - wrong alignof(double) on x86.
CWG 1879 - Inadequate definition of alignment requirement.
* cp-tree.h (ALIGNOF_EXPR_STD_P): New.
* typeck.c (cxx_sizeof_or_alignof_type): Add std_alignof parm.
(cxx_sizeof_expr, cxx_sizeof_nowarn, cxx_alignas_expr)
(cxx_alignof_expr): Pass it.
* parser.c (cp_parser_unary_expression): Pass it.
* pt.c (tsubst_copy): Copy it.
(tsubst_copy_and_build): Pass it.
* decl.c (fold_sizeof_expr): Pass it.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@259578 138bc75d-0d04-0410-961f-82ee72b054a4