[mojo-edk] Make the Mojo EDK compile under NaCl.

mojo/edk/system/BUILD.gn

Index: mojo/edk/system/BUILD.gn
diff --git a/mojo/edk/system/BUILD.gn b/mojo/edk/system/BUILD.gn
index daf93e475472da881c57be7d273e63013d35a29d..dd153d6b1bc1a7253c58528edb558f3ed49263c8 100644
--- a/mojo/edk/system/BUILD.gn
+++ b/mojo/edk/system/BUILD.gn
@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/nacl/config.gni")
 import("//testing/test.gni")
 import("../../../mojo/public/tools/bindings/mojom.gni")
 
@@ -100,9 +101,12 @@ component("system") {
   deps = [
     "//base",
     "//base/third_party/dynamic_annotations",
-    "//crypto",
   ]
 
+  if (!is_nacl) {
+    deps += [ "//crypto" ]
+  }
+
   if (is_win) {
     cflags = [ "/wd4324" ]  # Structure was padded due to __declspec(align()),
                             # which is uninteresting.
@@ -115,6 +119,14 @@ component("system") {
     ]
   }
 
+  if (is_nacl && !is_nacl_nonsfi) {
+    sources -= [
+      "broker_host_posix.cc",
+      "broker_posix.cc",
+      "channel_posix.cc",
+    ]
+  }
+
   allow_circular_includes_from = [ "//mojo/edk/embedder" ]
 }