clib2 Code

- Changed the algorithm that calculates the number of days that have passed
so far as used by the the __convert_time() function and the conversion
code in strftime().

- Also changed the algorithm used by strftime() to produce the week numbers
(the '%U' and '%W' format specifiers). The new method is much simpler
than the old one.

- Made the code that converts a 'time_t' value into the 'struct DateStamp',
as used by strftime() and utime(), into its own function. This also
fixes a bug in the code strftime() would use which was completely
unaware of the local time zone settings.

- We also test the strftime() %U, %W and %j format specifiers.

- Plugged in a different algorithm for calculating the day of the week in
strftime() and asctime_r(). This one isn't sensitive to the effects of
adding/subtracting the local time zone.

- Added a missing file.

- Updated the .cvsignore file.

- The general test program now also exercises the time conversion functions.

- mktime() is supposed to convert the time specification, given as local
time, into the number of seconds since January 1st, 1970, relative to
UTC. This didn't really work up until now since the time value returned
was given as local time.

- Moved the common DateStamp to time_t conversion code into a shared
function.

- The fall-back function for converting time into a string in strftime()
now calls itself for the "%x" and "%X" format specifiers.

- Added instructions for switching over an existing Amiga 68k GCC installation
to use "clib2".

- Added a check against DBL_EPSILON in log() and log10() in place of the
check against 0 that used to be in there.

- The default console output window opened when a program is launched
from Workbench would open and stay open. This was not intended to
happen and is a side-effect of the new stdio initialization code which
checks if the stdio streams are in non-blocking mode. Fixed.