Backport 2002-04-24 fix from newer linuxthreads versions to avoid hangs

or busy wait loop due to race between timeout and pthread_cond_signal.

devel/linuxthreads/Makefile

@@ -7,7 +7,7 @@
 
 PORTNAME=	linuxthreads
 PORTVERSION=	2.2.3
-PORTREVISION=	19
+PORTREVISION=	20
 CATEGORIES=	devel
 MASTER_SITES=	${MASTER_SITE_GNU}
 MASTER_SITE_SUBDIR=	glibc

devel/linuxthreads/files/patch-spinlock.c

@@ -0,0 +1,59 @@
+--- spinlock.c.orig	Tue Mar 27 04:52:56 2001
++++ spinlock.c	Tue Jan 10 09:44:39 2006
+@@ -72,8 +72,6 @@
+ #endif
+ 
+ #if defined HAS_COMPARE_AND_SWAP
+-again:
+-
+   /* On SMP, try spinning to get the lock. */
+ 
+   if (__pthread_smp_kernel) {
+@@ -94,6 +92,8 @@
+     lock->__spinlock += (spin_count - lock->__spinlock) / 8;
+   }
+ 
++again:
++
+   /* No luck, try once more or suspend. */
+ 
+   do {
+@@ -110,7 +110,7 @@
+     }
+ 
+     if (self != NULL) {
+-      THREAD_SETMEM(self, p_nextlock, (pthread_descr) (oldstatus & ~1L));
++      THREAD_SETMEM(self, p_nextlock, (pthread_descr) oldstatus);
+       /* Make sure the store in p_nextlock completes before performing
+          the compare-and-swap */
+       MEMORY_BARRIER();
+@@ -188,7 +188,7 @@
+        multiprocessor Alphas) could perform such reordering even though
+        the loads are dependent. */
+     READ_MEMORY_BARRIER();
+-    thr = *ptr;
++    thr = (pthread_descr)((long)(thr->p_nextlock) & ~1L);
+   }
+   /* Prevent reordering of the load of lock->__status above and
+      thr->p_nextlock below */
+@@ -198,17 +198,16 @@
+     /* If max prio thread is at head, remove it with compare-and-swap
+        to guard against concurrent lock operation. This removal
+        also has the side effect of marking the lock as released
+-       because the new status comes from thr->p_nextlock whose
+-       least significant bit is clear. */
++       by clearing the least significant bit. */
+     thr = (pthread_descr) (oldstatus & ~1L);
+     if (! __compare_and_swap_with_release_semantics
+-	    (&lock->__status, oldstatus, (long)(thr->p_nextlock)))
++	    (&lock->__status, oldstatus, (long)(thr->p_nextlock) & ~1L))
+       goto again;
+   } else {
+     /* No risk of concurrent access, remove max prio thread normally.
+        But in this case we must also flip the least significant bit
+        of the status to mark the lock as released. */
+-    thr = *maxptr;
++    thr = (pthread_descr)((long)*maxptr & ~1L);
+     *maxptr = thr->p_nextlock;
+ 
+     do {