From Albert Luaces, typo fixes.

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14883 16af8721-9629-0410-8352-f15c8da7e697

src/OpenThreads/pthreads/PThreadBarrier.cpp

@@ -75,13 +75,13 @@ Barrier::Barrier(int numThreads) {
     //
     //  PRIO_INHERIT causes any thread locking the mutex to temporarily become
     //  the same priority as the highest thread also blocked on the mutex. 
-    //  Although more expensive, this is the prefered method.
+    //  Although more expensive, this is the preferred method.
     //
     //  PRIO_PROTECT causes any thread locking the mutex to assume the priority
     //  specified by setprioceiling.  pthread_mutex_lock will fail if
     //  the priority ceiling is lower than the thread's priority.  Therefore,
     //  the priority ceiling must be set to the max priority in order to 
-    //  garantee no deadlocks will occur.
+    //  guarantee no deadlocks will occur.
     //
 #if defined (_POSIX_THREAD_PRIO_INHERIT) || defined (_POSIX_THREAD_PRIO_PROTECT) // [
 

src/OpenThreads/pthreads/PThreadMutex.cpp

@@ -64,13 +64,13 @@ Mutex::Mutex(MutexType type):
     //
     //  PRIO_INHERIT causes any thread locking the mutex to temporarily become
     //  the same priority as the highest thread also blocked on the mutex. 
-    //  Although more expensive, this is the prefered method.
+    //  Although more expensive, this is the preferred method.
     //
     //  PRIO_PROTECT causes any thread locking the mutex to assume the priority
     //  specified by setprioceiling.  pthread_mutex_lock will fail if
     //  the priority ceiling is lower than the thread's priority.  Therefore,
     //  the priority ceiling must be set to the max priority in order to 
-    //  garantee no deadlocks will occur.
+    //  guarantee no deadlocks will occur.
     //
 #if defined (_POSIX_THREAD_PRIO_INHERIT) || defined (_POSIX_THREAD_PRIO_PROTECT) // [
 

src/OpenThreads/win32/Win32Thread.cpp

@@ -161,7 +161,7 @@ namespace OpenThreads {
 
         //--------------------------------------------------------------------------
         // Set thread scheduling parameters.
-        // Note that time-critical priority is ommited :
+        // Note that time-critical priority is omitted :
         // 1) It's not sensible thing to do
         // 2) there's no enum for that in Thread interface
         // Also, on Windows, effective thread priority is :