[rfa/testsuite] 64-bit bigcore.exp fixes

[Andrew Cagney]

> Okay, approved.

It's in.

I forgot to mention that Dave Anderson (@redhat) came up with the seek 
trick, I added his name to the ChangeLog before committing.

thanks,
Andrew

> 2004-09-24  Andrew Cagney  <cagney@redhat.com>
> 
> 	* gdb.base/bigcore.exp (extract_heap): If the expect "file size"
> 	command fails, assume things will work.
> 	* gdb.base/bigcore.c: Include <sys/stat.h> and <fcntl.h>.
> 	(_GNU_SOURCE): Define.
> 	(print_unsigned, print_hex): Change parameter to "long long".
> 	(print_byte_count): New function, use to print byte counts.
> 	(large_off_t, large_lseek, O_LARGEFILE): Define dependant on
> 	O_LARGEFILE.
> 	(main): Compute an upper bound on a corefile in max_core_size.
> 	Limit memory chunk size to max_core_size.  Limit total memory
> 	allocated to max_core_size.