Merge remote-tracking branch 'stefanha/tracing' into staging

* stefanha/tracing:
  trace/simple: Replace asprintf by g_strdup_printf
  trace/simple: Fix compiler warning for 32 bit hosts
  trace: avoid pointer aliasing in trace_record_finish()
  trace: drop unused TraceBufferRecord->next_tbuf_idx field
  trace: remove unnecessary write_to_buffer() typecasting
  trace: rename TraceRecordHeader to TraceLogHeader