clib2 Code

- fstat() now works with "NIL:" and "/dev/null", respectively. Not that
it returns much useful information, though.

- Added the fstat() test program.

- The _PC_MAX_INPUT query for file handles now returns the default
buffer size.

- Integrated the new OS4 build makefile collection, as contributed by
Steven Solie. Thank you very much!

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- fpathconf() should work with the stdio streams, even in the thread-safe
library version, again.

- Added a new callback function which can be used in programs which want
to avoid that the command line wildcard expansion takes place.

- updated m68k specs file in /documentation to contain an own __CLIB2__
define so that existing m68k compilers also have this define. In addition,
the common "-noixemul" option can now also be specified but will do a NOP
so that Makefiles sharing multiple runtime lib setups work without
a warning.

- __get_default_file() now dynamically fills in file handles for the
stdin/stdout/stderr streams if it's part of the thread-safe library.

- fpathconf() now checks if the file descriptor is really referring to a file.

- The termios hook entry code could file descriptor's embedded file handle
rather than what the thread safe library had dynamically bound to the
stdin/stdout/stderr streams.

- execve() now finds commands in the current directory again, even if you
omit the leading "./" path name.