Add dupstr() as a substitute for strdup() so that out-of-memory
handling will be consistent with the rest of nethack, and make it aware
of nethack's heap logging. It's treated like alloc() so that its caller
can be logged for NH_HEAPLOG.
I put it into use in a few places, but there are lots more candidates
besides the existing calls to strdup() that should be replaced.
Hide pointer formatting in alloc.c by eliminating the need for callers
to know how big a buffer is required. I generally prefer the caller to
pass in its own buffer for this sort of thing, but in this case the usage
is almost entirely for debugging so using static buffers results in less
clutter in the rest of the code.
