Fix gRPC build failure on Android with Clang.

BUILD.gn

 # GRPC Chromium BUILD.gn file.
 # This file has been automatically generated from a template file.
 # Please look at the templates directory instead.
 # This file can be regenerated from the template by running
 # tools/buildgen/generate_projects.sh
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
 }
 
@@ skipping 121 matching lines @@
     "src/core/lib/support/time.c",
     "src/core/lib/support/time_posix.c",
     "src/core/lib/support/time_precise.c",
     "src/core/lib/support/time_windows.c",
     "src/core/lib/support/tls_pthread.c",
     "src/core/lib/support/tmpfile_msys.c",
     "src/core/lib/support/tmpfile_posix.c",
     "src/core/lib/support/tmpfile_windows.c",
     "src/core/lib/support/wrap_memcpy.c",
   ]
+  if (is_android) {
+    # gRPC memcpy wrapping logic isn't Android-friendly.
+    # See https://crbug.com/661171
+    sources -= [
+      "src/core/lib/support/wrap_memcpy.c",
+    ]
+  }
   deps = [
   ]
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [
     "//build/config/compiler:no_chromium_code",
   ]
   public_configs = [
     ":grpc_config",
   ]
 }
@@ skipping 1408 matching lines @@
     "//third_party/protobuf:protobuf_config",
   ]
   public_configs = [ ":grpc_config" ]
 }
 
 }