Build native client files only if enable_nacl is true.

Native client is unsupported on AArch64 Linux and building
its files unconditionally caused build failure.

BUG=666690

Review-Url: https://codereview.chromium.org/2511363002
Cr-Commit-Position: refs/heads/master@{#433511}

diff --git a/AUTHORS b/AUTHORS
index aa2f0ed..d32f45d 100644
--- a/AUTHORS
+++ b/AUTHORS

@@ -139,6 +139,7 @@
 Clinton Staley <clintstaley@chromium.org>
 Clinton Staley <clintstaley@gmail.com>
 Craig Schlenter <craig.schlenter@gmail.com>
+Csaba Osztrogonác <ossy.szeged@gmail.com>
 Daegyu Lee <na7jun8gi@gmail.com>
 Dai Chunyang <chunyang.dai@intel.com>
 Daiwei Li <daiweili@suitabletech.com>

diff --git a/BUILD.gn b/BUILD.gn
index 43c7b3d1..4eb68fc 100644
--- a/BUILD.gn
+++ b/BUILD.gn

@@ -780,7 +780,6 @@
       "//components/sessions:unit_tests",
       "//media/blink:media_blink_unittests",
       "//media/cast:udp_proxy",
-      "//native_client/src/trusted/debug_stub:gdb_rsp_unittest",
       "//storage/browser:dump_file_system",
       "//third_party/angle:libANGLE",
       "//third_party/angle:libEGL",
@@ -815,6 +814,10 @@
       "//ui/shell_dialogs:shell_dialogs_unittests",
     ]
 
+    if (enable_nacl) {
+      deps += [ "//native_client/src/trusted/debug_stub:gdb_rsp_unittest" ]
+    }
+
     if (target_cpu == "x86" || target_cpu == "x64") {
       if (!is_android) {
         deps += [ "//chrome/test:load_library_perf_tests" ]