Merge branch 'ds/bundle-uri'

Preliminary code refactoring around transport and bundle code.

* ds/bundle-uri:
  bundle.h: make "fd" version of read_bundle_header() public
  remote: allow relative_url() to return an absolute url
  remote: move relative_url()
  http: make http_get_file() external
  fetch-pack: move --keep=* option filling to a function
  fetch-pack: add a deref_without_lazy_fetch_extended()
  dir API: add a generalized path_match_flags() function
  connect.c: refactor sending of agent & object-format

path.c

@@ -1413,7 +1413,7 @@ int is_ntfs_dotgit(const char *name)
 
 	for (;;) {
 		c = *(name++);
-		if (!c || c == '\\' || c == '/' || c == ':')
+		if (!c || is_xplatform_dir_sep(c) || c == ':')
 			return 1;
 		if (c != '.' && c != ' ')
 			return 0;