* c-decl.c (grokdeclarator): Support flexible array members.

    * c-decl.c (grokdeclarator): Support flexible array members.
        Use open-ended ranges for these and zero-length arrays.
        * c-typeck.c (push_init_level): Validate the context of
        initialization of a zero-length array.
        * tree.c (int_fits_type_p): Be prepared for missing bounds.
        * varasm.c (array_size_for_constructor): New.
        (output_constructor): Use it for arrays of unspecified length.
        * extend.texi (Zero Length): Mention C99 flexible array members.
        Document initialization in a top-level struct as valid.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@37576 138bc75d-0d04-0410-961f-82ee72b054a4