New comment by dkwo on void-packages repository

https://github.com/void-linux/void-packages/pull/29635#issuecomment-808875418

Comment:
@tornaria Thanks, I'll be fine doing as you propose. Also, adding those packages would be great.
@ericonr I made changes, but feel free to close this if we decide to do otherwise.
My reason was that in sage-9.3.beta9 I get
```
cat build/pkgs/pari/spkg-configure.m4 | grep pthread
                     AC_MSG_CHECKING([whether pari is configured with pthreads])
                        [[return strcmp(PARI_MT_ENGINE, "pthread") != 0]])],
```