Additions/fixes for Tru64 syscall emulation.

Additions/fixes for Tru64 syscall emulation.
We can now run the SimpleScalar wupwise binary
to completion on the test input.
Didn't have time to do more testing, but I fixed
a major problem w/getdirentries that should help
a lot more programs run.

arch/alpha/alpha_tru64_process.cc:
    Add truncate, ftruncate, statfs, and fstatfs.
    Add v4.x (pre-F64) stat, fstat, and lstat.
    Add setsysinfo (though all it does is provide more
    specific warning messages).
    Fix subtle but major bug in getdirentries.
sim/syscall_emul.cc:
sim/syscall_emul.hh:
    Add truncate, ftruncate, statfs, and fstatfs.

--HG--
extra : convert_revision : 9037393d00dc49b0074a41603ea647587f5a9ec7