Request for comments: pthread dependency

[edsko]

Note

I don't know what the right answer is here. Perhaps this PR should be just be closed as wrong.

In crypton.cabal we have

if os(linux)
        extra-libraries: pthread

This was introduced in haskell-crypto#184 . I don't understand the issue well enough at all, perhaps this is actually required in some setups (perhaps only when the gold linker is used?). However, on my machine at least, this line does not appear to be necessary (both with and without -threaded), and https://stackoverflow.com/a/62561519/742991 suggests that -lpthread is deprecated.

It's causing some issues in some circumstances (e.g., see my trace-foreign-calls plugin), when ghc tries to load crypton dynamically, resulting in something like

<command line>: User-specified static library could not be loaded (/usr/lib/gcc/x86_64-linux-gnu/13/../../../x86_64-linux-gnu/libpthread.a)
Loading static libraries is not supported in this configuration.
Try using a dynamic library instead.

Related: https://gitlab.haskell.org/ghc/ghc/-/issues/12816 (which adds the dependency, to be clear, not remove it).

[edsko]

After having discussed this with a colleague, I believe the better approach is #33. Closing this.

[kazu-yamamoto]

I made a mistake.
I accidentally merged #33, so reverted it, and merge this PR by hand.

[edsko]

Ok, perfect, then I'll delete my branch. Thanks!