[NaCl SDK] nacl_io: Fix newlib IRT interception of isatty().

native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc

Index: native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
index 50dbe6e14da75c3f3243016c3d95aae17cb9542b..049e53b4925afb050d387966848bd7260ad6804a 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
@@ -161,7 +161,7 @@ int WRAP(ftruncate)(int fd, off_t length) {
 
 int WRAP(isatty)(int fd, int* result) {
   *result = ki_isatty(fd);
-  if (*result == 1)
+  if (*result == 0)
     return errno;
   return 0;
 }