decompress testsuite fails 5.0 because of missing pthread link flag

[moyodiallo]

Hi,

I found this issue on OPAM health check, it's about the decompress package.

The main.c file include caml/callback.h,the ocaml-multicore runtime now use pthread by default, we get this error because of that :

$ cc -o a.out main.c -I$(ocamlopt -where) -L../../bindings/stubs -I../../bindings/stubs -ldecompress -lm -ldl 
+  ../../bindings/stubs/libdecompress.a(decompress.exe.o): In function `caml_execute_signal_exn':
+  /home/alpha/.opam/multicore/.opam-switch/build/ocaml-variants.4.14.0+domains/runtime/signals.c:191: undefined reference to `pthread_sigmask'

By adding -lpthread to the command, it work fine. I think, we should precise in ocaml-multicore's doc that linking pthread is now a requirement when linking the OCaml runtime.

[moyodiallo]

It's same issue with tplib package. Solving this issue is just adding the flag -lpthread in configure.ac file at line 44 (same as -lm) and after not forget to regenerate the config file by the command autogen -i -f