gdb patch for 64-bit enum values on 64-bit hosts (ia64-linux)

[Jim Blandy]

I'm going on vacation, and won't be able to look at this until the
10th.

- I pointed out places in dwarf2read.c that need to be expanded to 
  handle DW_FORM_data8.
- JimW's patch at least identifies all the code that needs to be
  changed if we expand enums, range values, etc to be a longer type.
- Andrew has provided instructions for how to handle LONGEST
  values in printing.

So I think all the facts are assembled to actually fix this.  But I
can't do it.