Fixed compiler warnings

mysys/stacktrace.c

@@ -173,7 +173,7 @@ void my_print_stacktrace(uchar* stack_bottom __attribute__((unused)),
     my_safe_printf_stderr("%s",
       "Error when traversing the stack, stack appears corrupt.\n");
   else
-    my_safe_printf_stderr("%s"
+    my_safe_printf_stderr("%s",
       "Please read "
       "http://dev.mysql.com/doc/refman/5.1/en/resolve-stack-dump.html\n"
       "and follow instructions on how to resolve the stack trace.\n"

sql/mysqld.cc

@@ -741,7 +741,6 @@ char *opt_logname, *opt_slow_logname;
 
 static volatile sig_atomic_t kill_in_progress;
 #ifdef HAVE_STACKTRACE
-static my_bool opt_do_pstack;
 my_bool opt_stack_trace;
 #endif /* HAVE_STACKTRACE */
 my_bool opt_expect_abort= 0;