clib2 Code

- Fixed the SAS/C destructor function prototypes and verified
that the constructors/destructors are called in the proper
order, too.

- The destructor function invocation code no longer calls
setjmp(). This is now done within stdlib_main.c prior to
calling the destructor function invocation code.

- Switched over the startup code and the library itself to use
constructor/destructor functions for initialization and cleanup
purposes.

This commit was manufactured by cvs2svn to create tag
'BEFORE_CONSTRUCTOR_CHANGE'.

- Introduced new constructor types and changed the overall priority
order.

- Moved data out of stdlib_data.c and into the code that references
or initializes it.

- The stdlib constructor now performs the CPU/FPU compatibility test.

- The macro definitions deserved better documentation. Well, they probably still do...

- Fixed another interesting bug in the OS4 destructor code.

- Corrected a typo in the OS4 destructor code.

- Added S_IREAD, S_IWRITE and S_IEXEC aliases to <sys/stat.h>.