I've just downloaded PosixGCCSimulator_6.0.4.zip, but when I try to build my project I find that timer.h is missing. And including timer.h from the FreeRTOS/include doesn't help as it renders lots of other error messages.
What is the procedure to get timer-definitions when running Posix simulator?
It sounds like you have a very old version. There are some updated
versions on the web, including in the FreeRTOS Interactive site:
Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.