Merge branch 'am/real-path-fix'

The real_path() convenience function can easily be misused; with a bit of code refactoring in the callers' side, its use has been eliminated. * am/real-path-fix: get_superproject_working_tree(): return strbuf real_path_if_valid(): remove unsafe API real_path: remove unsafe API set_git_dir: fix crash when used with real_path()