Remove "tree->entries" tree-entry list from tree parser

This finally removes the tree-entry list from "struct tree", since most of
the users can just use the tree-walk infrastructure to walk the raw tree
buffers instead of the tree-entry list.

The tree-entry list is inefficient, and generates tons of small
allocations for no good reason. The tree-walk infrastructure is generally
no harder to use than following a linked list, and allows us to do most
tree parsing in-place.

Some programs still use the old tree-entry lists, and are a bit painful to
convert without major surgery. For them we have a helper function that
creates a temporary tree-entry list on demand. We can convert those too
eventually, but with this they no longer affect any users who don't need
the explicit lists.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-ls-tree.c

@@ -53,7 +53,7 @@ static int show_recursive(const char *base, int baselen, const char *pathname)
 	}
 }
 
-static int show_tree(unsigned char *sha1, const char *base, int baselen,
+static int show_tree(const unsigned char *sha1, const char *base, int baselen,
 		     const char *pathname, unsigned mode, int stage)
 {
 	int retval = 0;