real_path: have callers use real_pathdup and strbuf_realpath

Migrate callers of real_path() who duplicate the retern value to use
real_pathdup or strbuf_realpath.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/setup.c b/setup.c
index fe572b8..1b534a7 100644
--- a/setup.c
+++ b/setup.c
@@ -256,8 +256,10 @@ int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
 		strbuf_addbuf(&path, &data);
 		strbuf_addstr(sb, real_path(path.buf));
 		ret = 1;
-	} else
+	} else {
 		strbuf_addstr(sb, gitdir);
+	}
+
 	strbuf_release(&data);
 	strbuf_release(&path);
 	return ret;
@@ -692,7 +694,7 @@ static const char *setup_discovered_git_dir(const char *gitdir,
 	/* --work-tree is set without --git-dir; use discovered one */
 	if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 		if (offset != cwd->len && !is_absolute_path(gitdir))
-			gitdir = xstrdup(real_path(gitdir));
+			gitdir = real_pathdup(gitdir);
 		if (chdir(cwd->buf))
 			die_errno("Could not come back to cwd");
 		return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
@@ -800,11 +802,12 @@ static int canonicalize_ceiling_entry(struct string_list_item *item,
 		/* Keep entry but do not canonicalize it */
 		return 1;
 	} else {
-		const char *real_path = real_path_if_valid(ceil);
-		if (!real_path)
+		char *real_path = real_pathdup(ceil);
+		if (!real_path) {
 			return 0;
+		}
 		free(item->string);
-		item->string = xstrdup(real_path);
+		item->string = real_path;
 		return 1;
 	}
 }