- make string comparisons case-insensitive
- add description of whitespace in the format string
- note that %t and %n match no whitespace as well as some whitespace
- change wording of standard to say "includes all requirements of"
instead of "conforms to" XPG4 as our %y is extended beyond XPG4
- %C and %y can be used in conjunction properly, though %y can have its
old behaviour if used without %C
- %I formats hous 0..11 with 0 representing "12"; this is correct both
with and without am/pm (%p rule fixed to compensate)
- %j fixed for range [0..365] in struct tm
- %m fixed for range [0..11] in struct tm
- %S fixed for range [0..61] in struct tm
tv