* thread.c (do_select): suppress warnings.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24715 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

thread.c

@@ -2355,7 +2355,7 @@ do_select(int n, fd_set *read, fd_set *write, fd_set *except,
 	  struct timeval *timeout)
 {
     int result, lerrno;
-    fd_set orig_read, orig_write, orig_except;
+    fd_set orig_read = {}, orig_write = {}, orig_except = {};
 
 #ifndef linux
     double limit = 0;