#14 PTRACE debug macro, const correctness

[Timothee Besset]

Attaching patch needed for cachefs code:

- disable wavfs (dunno how to make it default off. cvs
is broken with wavfs. might need rework)

- make lu_cache_add2dir const correct

- add a PTRACE C++ debug macro. this prints the
complete function name. it's a gcc extension so I
suspect it might need to be tested at configure time

[Timothee Besset]

the patch