This is intended to be a complete implementation of strftime as specified in C17, although it lacks meaningful support for time zones or non-C locales.
This may be either 50 or 60, depending on the system's video frequency setting (50Hz PAL or 60Hz NTSC). The video setting can be determined by inspecting bit 4 of the LANGSEL soft switch, documented in Appendix E of the Apple IIGS Firmware Reference.
Tabs have been expanded to spaces in several files that use mainly spaces for indentation.
The files ctype.asm, stdio.asm, and string.asm consistently use tabs for indentation. The tabs in these files have been left alone, except that a few tabs between sentences in comments were changed to spaces. One space-indented line in stdio.asm was changed to use a tab.
This could happen when it was called for a time other than the present, because it set tm_isdst based on the current value of the DST flag in BRAM, which is valid only for the current time.
Now it works as follows: If localtime() is passed the time_t value that was produced by the most recent call to time(), it gives the DST setting in effect at the time of that call. Otherwise, it sets tm_isdst to -1, indicating that the correct value is unknown.
This is about the best we can do without having a full timezone library/database. It should give the right tm_isdst value in probably the most common case, and avoids giving an incorrect value in any case (assuming the system's DST flag is right).
This fixes#18.
Stephen Heumann
Kelvin Sherlock
mikew50