PATCH: comment fix in libstdc++

[Ben Elliston]

Found as part of a search for other errors of its (not it's) kind ;-).
Committed as obvious.

Cheers, Ben 

2008-08-26  Ben Elliston  <bje@au.ibm.com>

        * src/mt_allocator.cc (__pool): Fix error in comment.

Index: libstdc++-v3/src/mt_allocator.cc
===================================================================
--- libstdc++-v3/src/mt_allocator.cc    (revision 139616)
+++ libstdc++-v3/src/mt_allocator.cc    (working copy)
@@ -610,7 +610,7 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
     // If we have thread support and it's active we check the thread
     // key value and return its id or if it's not set we take the
     // first record from _M_thread_freelist and sets the key and
-    // returns it's id.
+    // returns its id.
     if (__gthread_active_p())
       {
        void* v = __gthread_getspecific(freelist._M_key);