clib2 Code

- The libunix.a flavour of system() no longer attempts to translate the name
of a command unless it contains path separator characters.

- Fixed a typo in the semaphore creation code. Ouch.

- If fread()/fwrite() fail to read/write any data because either the number
of records or the size of each record is zero, both now call clearerr() to
avoid giving the caller the wrong impression that an EOF or error occured.

- Fixed two linker errors which were caused by duplicate symbol definitions.

- Added code to the startup routine which allows you to monitor where command
was started from and which parameters it was invoked with.

- Fixed two linker errors which were caused by duplicate symbol definitions.

- Added code to the startup routine which allows you to monitor where command
was started from and which parameters it was invoked with.

- The record locking semaphore could wind up getting added to the public
list twice. Fixed.

- Changed how errors are detected, as returned by Write(), Read() and
Seek(). Seek() is particularly challenging because the value it
returns might be a valid file position and not an error.

- Replaced numeric function return codes of 0 and -1 with macros OK,
SEEK_ERROR/ERROR to clarify the respective purposes.

- Changed how ftell() and fseek() are used, double-checking the return
value and the errno code.

- Changed how error conditions raised by dos.library file I/O functions
are detected.

- Modified function return values of 0 and -1 to use macros like OK,
ERROR/SEEK_ERROR instead, to better convey what the purpose of these
values is.

- Reversed the change in rename() which enforced deletion of the target file.

- The Unix-like rename() now removes the target file even if that
file has been protected from deletion.