added several system call hooks for future sockets implementation

elf/Versions

Index: elf/Versions
diff --git a/elf/Versions b/elf/Versions
index e7222178ac686cb17ed5414777ecbdf67b103ff8..d6ba458bf5bfc1b5fe40d866de21e5acf1b8a710 100644
--- a/elf/Versions
+++ b/elf/Versions
@@ -102,6 +102,7 @@ ld {
     __nacl_irt_open;
     __nacl_irt_open_resource;
     __nacl_irt_read;
+    __nacl_irt_write;
     __nacl_irt_sched_yield;
     __nacl_irt_seek;
     __nacl_irt_stat;
@@ -112,7 +113,32 @@ ld {
     __nacl_irt_thread_nice;
     __nacl_irt_tls_get;
     __nacl_irt_tls_init;
-    __nacl_irt_write;
+    __nacl_irt_epoll_create;
+    __nacl_irt_epoll_create1;
+    __nacl_irt_epoll_ctl;
+    __nacl_irt_epoll_wait;
+    __nacl_irt_epoll_pwait;
+    __nacl_irt_poll;
+    __nacl_irt_ppoll;
+    __nacl_irt_socket;
+    __nacl_irt_accept;
+    __nacl_irt_bind;
+    __nacl_irt_send;
+    __nacl_irt_recv;
+    __nacl_irt_listen;
+    __nacl_irt_connect;
+    __nacl_irt_sendto;
+    __nacl_irt_recvfrom;
+    __nacl_irt_select;
+    __nacl_irt_pselect;
+    __nacl_irt_sendmsg;
+    __nacl_irt_recvmsg;
+    __nacl_irt_getpeername;
+    __nacl_irt_getsockname;
+    __nacl_irt_getsockopt;
+    __nacl_irt_setsockopt;
+    __nacl_irt_socketpair;
+    __nacl_irt_shutdown;
     # Those are in the dynamic linker, but used by libc.so.
     __libc_enable_secure;
     _dl_argv;