lint cleanup to pacify gcc

lint cleanup to pacify gcc

I upgraded from OSX 10.5.8 via 10.6.3 to 10.6.8, plus Xcode to whatever
version was on the 10.6 dvd, and ended up with a more recent version of
gcc that is configured to use 64 bit longs and 64 bit pointers (by
default; presumably that can be changed if necessary).  It triggered
several warnings about converting int to pointer of different size or
vice versa even when explicit casts were in use, and a couple of other
things.