Please test new NSLock implementation!

[David Chisnall]

Hi Everyone,

I've just committed a new version of all of the NSLock family of  
classes to GNUstep-base, and a slightly reworked NSThread.  Bugs in  
this code have the potential to break any multithreaded applications,  
so please test them on your favourite platform, with your favourite  
applications.  And on platforms you hate with apps you can't stand,  
for that matter.

As a result of this change, GNUstep now depends directly on POSIX  
threads.  If you are building on Windows, you will need to download  
the pthread-win32 package from here:

http://sourceware.org/pthreads-win32/

I apologise for this extra dependency for Windows users, but it's  
probably better than the existing implementation which called this  
function to create a condition lock:

/* Allocate a condition. */
int
__objc_condition_allocate(objc_condition_t condition)
{
  /* Unimplemented. */
  return -1;
}

On most other *NIX systems you should have pthreads available by  
default.  I don't know if anyone's building GNUstep in the Symbian or  
QNX POSIX layer (let me know if you are), but pthread implementations  
are available here too.  The MIT Pthreads package provides a pure  
userspace (N:1) implementation of pthreads on almost any UNIX-like  
system, so should work for people using ancient UNIX (the pthread  
specification was released in 1996 and is supported on most UNIX  
systems that are less than a decade old; some of the more obscure  
corners are not well-supported, but we're not using any of those).

David