Fixed "unused private field" warning for clang.

Bug: 17095037
Change-Id: Iedbe56f6ddc0ba7876896b0bb7ed9da8e6a85f7e
Tested: on Linux & OS X.

src/idl_gen_cpp.cpp

@@ -376,7 +376,16 @@ static void GenStruct(StructDef &struct_def, std::string *code_ptr) {
     if (field.padding)
       code += ", __padding" + NumToString(padding_id++) + "(0)";
   }
-  code += " {}\n\n";
+  code += " {";
+  padding_id = 0;
+  for (auto it = struct_def.fields.vec.begin();
+       it != struct_def.fields.vec.end();
+       ++it) {
+    auto &field = **it;
+    if (field.padding)
+      code += " (void)__padding" + NumToString(padding_id++) + ";";
+  }
+  code += " }\n\n";
 
   // Generate accessor methods of the form:
   // type name() const { return flatbuffers::EndianScalar(name_); }

tests/monster_test_generated.h

@@ -47,7 +47,7 @@ MANUALLY_ALIGNED_STRUCT(2) Test {
 
  public:
   Test(int16_t a, int8_t b)
-    : a_(flatbuffers::EndianScalar(a)), b_(flatbuffers::EndianScalar(b)), __padding0(0) {}
+    : a_(flatbuffers::EndianScalar(a)), b_(flatbuffers::EndianScalar(b)), __padding0(0) { (void)__padding0; }
 
   int16_t a() const { return flatbuffers::EndianScalar(a_); }
   int8_t b() const { return flatbuffers::EndianScalar(b_); }
@@ -68,7 +68,7 @@ MANUALLY_ALIGNED_STRUCT(16) Vec3 {
 
  public:
   Vec3(float x, float y, float z, double test1, int8_t test2, const Test &test3)
-    : x_(flatbuffers::EndianScalar(x)), y_(flatbuffers::EndianScalar(y)), z_(flatbuffers::EndianScalar(z)), __padding0(0), test1_(flatbuffers::EndianScalar(test1)), test2_(flatbuffers::EndianScalar(test2)), __padding1(0), test3_(test3), __padding2(0) {}
+    : x_(flatbuffers::EndianScalar(x)), y_(flatbuffers::EndianScalar(y)), z_(flatbuffers::EndianScalar(z)), __padding0(0), test1_(flatbuffers::EndianScalar(test1)), test2_(flatbuffers::EndianScalar(test2)), __padding1(0), test3_(test3), __padding2(0) { (void)__padding0; (void)__padding1; (void)__padding2; }
 
   float x() const { return flatbuffers::EndianScalar(x_); }
   float y() const { return flatbuffers::EndianScalar(y_); }