[fpc-pascal] single application instance

[Marco van de Voort]

> > How can I also do it in linux?
> 
> Use semaphores. There is a semaphore implementation for LINUX, Windows, BeOS
> and probably most other Unices. Certainly, any platform that conforms to
> POSIX and/or PThreads will have a semaphore implementation.
> 
> The mechanics will be different - the idea will be universal.

For *nix it is in unit ipc.