Merge 'jk/git-path' into kn/for-each-tag

* jk/git-path: memoize common git-path "constant" files get_repo_path: refactor path-allocation find_hook: keep our own static buffer refs.c: remove_empty_directories can take a strbuf refs.c: avoid git_path assignment in lock_ref_sha1_basic refs.c: avoid repeated git_path calls in rename_tmp_log refs.c: simplify strbufs in reflog setup and writing path.c: drop git_path_submodule refs.c: remove extra git_path calls from read_loose_refs remote.c: drop extraneous local variable from migrate_file prefer mkpathdup to mkpath in assignments prefer git_pathdup to git_path in some possibly-dangerous cases add_to_alternates_file: don't add duplicate entries t5700: modernize style cache.h: complete set of git_path_submodule helpers cache.h: clarify documentation for git_path, et al