use thread_local for ntoa buf

@@ -681,11 +681,10 @@
 #if defined(sparc)
         void            *ul_unwind_ret; /* used only by _ex_clnup_handler() */
 #endif
         tumem_t         ul_tmem;        /* used only by umem */
         uint_t          ul_ptinherit;   /* pthreads sched inherit value */
-        char            ul_ntoabuf[18]; /* thread-specific inet_ntoa buffer */
 } ulwp_t;
 
 #define ul_cursig       ul_cp.s.cursig          /* deferred signal number */
 #define ul_pleasestop   ul_cp.s.pleasestop      /* lwp requested to stop */
 #define ul_curplease    ul_cp.curplease         /* for testing both at once */