Merge branch 'jk/parse-int' into seen

Merge branch 'jk/parse-int' into seen

Introduce a more robust way to parse a decimal integer stored in a
piece of memory that is not necessarily terminated with NUL (which
Asan strict-string-check complains even when use of strtol() is
safe due to varified existence of whitespace after the digits).

* jk/parse-int:
  fsck: use parse_unsigned_from_buf() for parsing timestamp
  cache-tree: use parse_int_from_buf()
  parse: add functions for parsing from non-string buffers
  parse: prefer bool to int for boolean returns