PR c/14411
        * calls.c (flags_from_decl_or_type): Handle eturns_twice' attribute.
        * c-common.c (handle_returns_twice): New function.
        (c_common_attribute_table): Declare eturns_twice' attribute.
        * doc/extend.texi: Document eturns_twice' attribute.
        * tree.h (DECL_IS_RETURNS_TWICE): New macro.
        (struct tree_decl): Add returns_twice_flag.

From-SVN: r96101