tar: Fix typo in patch file

R=binji@chromium.org

Review URL: https://codereview.chromium.org/815353007
diff --git a/ports/tar/nacl.patch b/ports/tar/nacl.patch
index 09fd2c5..61b3423 100644
--- a/ports/tar/nacl.patch
+++ b/ports/tar/nacl.patch
@@ -5,7 +5,7 @@
  # define MATCHING_INO(dp, ino) true
  #endif
  
-+#ifdef __native_client__ && defined _NEWLIB_VERSION
++#if defined __native_client__ && defined _NEWLIB_VERSION
 +/* openat() is currently non-existent for newlib builds, but AT_FDCWD is
 +   present in the headers.  Explicatly undefine it here to avoid use of
 +   openat().