default dir not working for Mac OS

[renepickhardt]

bitcoin-iterate/blockfiles.c

Line 45 in 5e82b67

/* First try new-style: $HOME/.bitcoin/blocks/blk[0-9]*.dat. */

has a distinction between the old directory format and the new one.

It might make sense to also add a distinction for MacOS as in Mac OS the blocks are stored at ~/Library/Application Support/Bitcoin/blocks/

[renepickhardt]

of course one can just use the --blockdir argument when calling the tool. eg: $ ./bitcoin-iterate --output='%bN' --blockdir='~/Library/Application Support/Bitcoin/blocks/'