Build nacl_helper_nonsfi with GN

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index e3dfffbacedc83b08e7cf963e773208abaeca049..c54cf94c4342597e877b1cd051116844de84740b 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -326,6 +326,25 @@ config("compiler") {
     cflags_cc += [ "-std=c++11" ]
   }
 
+  if (is_nacl_nonsfi) {
+    cflags += [
+      "--target=i686-unknown-nacl",
+      "--pnacl-bias=x86-32-nonsfi",
+      "-arch",
+      "x86-32-nonsfi",
+      "--pnacl-allow-native",
+      "--pnacl-allow-translate",
+    ]
+
+    ldflags += [
+      "-arch",
+      "x86-32-nonsfi",
+      "--pnacl-allow-native",
+    ]
+
+    include_dirs = [ "//native_client/src/public/linux_syscalls" ]
+  }
+
   # Pass the same C/C++ flags to the objective C/C++ compiler.
   cflags_objc += cflags_c
   cflags_objcc += cflags_cc
@@ -743,6 +762,19 @@ config("default_warnings") {
         "-Wno-bitfield-width",
       ]
     }
+
+    if (is_nacl_nonsfi) {
+      cflags += [
+        # Disables
+        "-Wno-c++11-extensions",
+        "-Wno-char-subscripts",
+        "-Wno-extra-semi",
+        "-Wno-unnamed-type-template-args",
+        "-Wno-unused-private-field",
+        "-Wno-unused-function",
+        "-Wno-sign-compare",
+      ]
+    }
   }
 }