[Haskell-cafe] Why do ghc-built binaries use timer_create?

[Maurí­cio]

This comes from an issue in haskell-beginner, although
it have already been touched here. If you use recent
versions of ghc to build a program and try the resulting
binary on an old linux distro, you may get a message
about timer_create receiving the wrong parameters.

Curiously, as sugested in the other thread, it seems
building with

ghc -threaded

solves the problem. So, I'm just curious: how is
timer_create used, and why maybe it's not used with
-threaded?

Thanks,
Maurício