clib2 Code

- We now call IsInteractive() rather than send a type ACTION_DISK_INFO
to a likely console handler file's MsgPort.

- Invoking fstat() on what maps to a con-handler stream now produces
information identifying it as a character special file. Side-effect:
if the input/output went to a CON:/AUTO window, that window will
pop open and stay open.

- File descriptors produced by dup() or dup2() now work exactly like
the original file descriptors they are duplicates of. I modified the
function which maps file descriptor numbers to file descriptor
table entries to return the table entries of the original files.

- In the thread-safe library, duplicated stdin/stdout/stderr
descriptors now work like the "real" ones. This is true even if
the "real" ones were closed and only their former aliases remain.

- Moved the __UtilityBase/__IUtility variable declarations into
a separate file.

- Simplified the library/open close code in "stdlib_main.c".

- raise() no longer resets the signal handler before it invokes the one
currently configured. It merely blocks the delivery of the respective
signal to prevent recursion.

- raise() now drops into abort() if a signal handler is set to
SIG_DFL. The exception is in SIGINT delivery, which has the
effect of printing a different termination message but otherwise
program flow takes the same path as abort().

- Moved the signal block mask and the signal function table out of
signal_data.c and into signal_raise.c where they are actually used.
This makes it possible to override the default definition of the
__check_abort_enabled variable in your own programs.

- The name of the public record locking semaphore has to be preallocated
for OS4 if the AllocSysObject() function is used to create it.

- Updated the specs file not to reference the main.o files any more.

- Clarified the caveats of the libm.a use.

- Ready for release...

- Oops, nearly broke fcntl() again for sockets.