save size for writing

tools/compilers/wav/WAVCompiler.cpp

@@ -68,6 +68,7 @@ size_t WAVCompiler::compile_impl(const char* resource_path)
 	}
 
 	m_sound_header.version = SOUND_VERSION;
+	m_sound_header.size = m_wav_header.data_size;
 	m_sound_header.channels = m_wav_header.fmt_channels;
 	m_sound_header.bits_per_sample = m_wav_header.fmt_bits_per_sample;