merge-tree: rename merge_trees() to trivial_merge_trees()

merge-recursive.h defined its own merge_trees() function, different than
the one found in builtin/merge-tree.c.  That was okay in the past, but
we want merge-tree to be able to use the merge-ort functions, which will
end up including merge-recursive.h.  Rename the function found in
builtin/merge-tree.c to avoid the conflict.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/merge-tree.c

@@ -28,7 +28,7 @@ static void add_merge_entry(struct merge_list *entry)
 	merge_result_end = &entry->next;
 }
 
-static void merge_trees(struct tree_desc t[3], const char *base);
+static void trivial_merge_trees(struct tree_desc t[3], const char *base);
 
 static const char *explanation(struct merge_list *entry)
 {
@@ -225,7 +225,7 @@ static void unresolved_directory(const struct traverse_info *info,
 	buf2 = fill_tree_descriptor(r, t + 2, ENTRY_OID(n + 2));
 #undef ENTRY_OID
 
-	merge_trees(t, newbase);
+	trivial_merge_trees(t, newbase);
 
 	free(buf0);
 	free(buf1);
@@ -342,7 +342,7 @@ static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, s
 	return mask;
 }
 
-static void merge_trees(struct tree_desc t[3], const char *base)
+static void trivial_merge_trees(struct tree_desc t[3], const char *base)
 {
 	struct traverse_info info;
 
@@ -378,7 +378,7 @@ int cmd_merge_tree(int argc, const char **argv, const char *prefix)
 	buf1 = get_tree_descriptor(r, t+0, argv[1]);
 	buf2 = get_tree_descriptor(r, t+1, argv[2]);
 	buf3 = get_tree_descriptor(r, t+2, argv[3]);
-	merge_trees(t, "");
+	trivial_merge_trees(t, "");
 	free(buf1);
 	free(buf2);
 	free(buf3);