Problem: Various inconsistencies in test files.
Solution: Add modelines where they were missing. Use Check commands instead
of silently skipping over tests. Adjust indents and comments.
(Ken Takata, closes#6695)
Problem: The "num64" feature is available everywhere and building without
it causes problems.
Solution: Graduage the "num64" feature. (James McCoy, closes#5650)
Problem: On MS-Windows large files (> 2Gbyte) cause problems.
Solution: Use "off_T" instead of "off_t". Use "stat_T" instead of "struct
stat". Use 64 bit system functions if available. (Ken Takata)
