* ada-lang.c: #include "vec.h".

    * ada-lang.c: #include "vec.h".
        (struct string_vector, new_string_vector, string_vector_append):
        Delete.
        (char_ptr): New typedef.
        (DEF_VEC_P (char_ptr)): New VEC type.
        (symbol_completion_add): Update profile to take the new VEC type
        instead of the old string_vector structure. Update code accordingly.
        (ada_make_symbol_completion_list): Use the new VEC type instead of
        the old string_vector structure, and update the code accordingly.
        * Makefile.in (ada-lang.o): Add dependency on vec.h.