add (overwrite with) mypy stubs, if available

stdlib/2.7/stat.pyi

@@ -0,0 +1,58 @@
+def S_ISDIR(mode: int) -> bool: ...
+def S_ISCHR(mode: int) -> bool: ...
+def S_ISBLK(mode: int) -> bool: ...
+def S_ISREG(mode: int) -> bool: ...
+def S_ISFIFO(mode: int) -> bool: ...
+def S_ISLNK(mode: int) -> bool: ...
+def S_ISSOCK(mode: int) -> bool: ...
+
+def S_IMODE(mode: int) -> int: ...
+def S_IFMT(mode: int) -> int: ...
+
+ST_MODE = 0
+ST_INO = 0
+ST_DEV = 0
+ST_NLINK = 0
+ST_UID = 0
+ST_GID = 0
+ST_SIZE = 0
+ST_ATIME = 0
+ST_MTIME = 0
+ST_CTIME = 0
+ST_IFSOCK = 0
+ST_IFLNK = 0
+ST_IFREG = 0
+ST_IFBLK = 0
+ST_IFDIR = 0
+ST_IFCHR = 0
+ST_IFIFO = 0
+S_ISUID = 0
+S_ISGID = 0
+S_ISVTX = 0
+S_IRWXU = 0
+S_IRUSR = 0
+S_IWUSR = 0
+S_IXUSR = 0
+S_IRGRP = 0
+S_IWGRP = 0
+S_IXGRP = 0
+S_IRWXO = 0
+S_IROTH = 0
+S_IWOTH = 0
+S_IXOTH = 0
+S_ENFMT = 0
+S_IREAD = 0
+S_IWRITE = 0
+S_IEXEC = 0
+UF_NODUMP = 0
+UF_IMMUTABLE = 0
+UF_APPEND = 0
+UF_OPAQUE = 0
+UF_NOUNLINK = 0
+UF_COMPRESSED = 0
+UF_HIDDEN = 0
+SF_ARCHIVED = 0
+SF_IMMUTABLE = 0
+SF_APPEND = 0
+SF_NOUNLINK = 0
+SF_SNAPSHOT = 0