Allow Java's ELF symtab reader to use separate debuginfo files

[Andrew Haley]

 Andrew Haley wrote:
> Kelly O'Hair wrote:
>> Is there some other way than baking in 256 hex constants into our sources?
>
> I'm sure it's perfectly possible to generate the CRC-32 tables at runtime.
> However, the CRC function is defined in terms of this exact source code,

Ah, I was about to add "but it's only 1 kbyte!" when I noticed that
the data are unsigned longs, and therefore maybe 2 kbytes.  I presume
that this is because gdb might be used on hosts with 16-bit ints, but
that hardly affects us.  I'll fix it before submitting a webrev.

Andrew.