Non-SFI mode: Add Linux asynchronous signal support

src/untrusted/nacl/nacl_ext_supply.c

Index: src/untrusted/nacl/nacl_ext_supply.c
diff --git a/src/untrusted/nacl/nacl_ext_supply.c b/src/untrusted/nacl/nacl_ext_supply.c
index 9c01da5bed71b08238a0b5895dd3e0cfd1931cee..95a4dc28e06a306579d4835de01798f69b5d6881 100644
--- a/src/untrusted/nacl/nacl_ext_supply.c
+++ b/src/untrusted/nacl/nacl_ext_supply.c
@@ -23,7 +23,7 @@
 extern struct nacl_irt_basic __libnacl_irt_basic __attribute__((weak));
 extern struct nacl_irt_fdio __libnacl_irt_fdio __attribute__((weak));
 extern struct nacl_irt_memory __libnacl_irt_memory __attribute__((weak));
-extern struct nacl_irt_thread __libnacl_irt_thread __attribute__((weak));
+extern struct nacl_irt_thread_v0_2 __libnacl_irt_thread __attribute__((weak));
 extern struct nacl_irt_futex __libnacl_irt_futex __attribute__((weak));
 extern struct nacl_irt_clock __libnacl_irt_clock __attribute__((weak));