Fix misspelled #define.
Ensure config.system_user_threshold is unsigned integer.
Include 'sys/stat.h' in bookkeeper.c for chmod (included by default by some, but
this is not supported behaviour).
Fix missing comma in printf statement.
Fix using _GNU_SOURCE when code is XOPEN+POSIX compatible. Use what you must,
not what you can.
Merge pull request #1 from necrophcodr/develop

Fix small compatability issues and reorder code to better conform with POSIX