Add two more packages for Debian/Ubuntu

If libtinfo5 isn't installed, then installation fails with a message like this: /home/ubuntu/.ghcup/ghc/8.6.5/lib/ghc-8.6.5/bin/ghc-pkg: error while loading shared libraries: libtinfo.so.5: cannot open shared object file: No such file or directory

If xz-utils isn't installed, then installation fails with a message like this: Following commands are required, but missing, please install: xz

These were removed by @leif in bbe32148

added 1 commit

• bea68cd8 - Remove xz-utils

Compare with previous version

Ah, xz-utils is indeed part of build-essential. I didn't realize that at first, as the error that xz is missing comes before it tells you that you need build-essential, so I had already installed the former before I installed the latter.

As for libtinfo5, since this file is shared between Debian and Ubuntu, there are still some cases where the bindist needs libtinfo.so.5 (such as Debian 10, which can be easily tested inside docker run -it debian:10). In those environments, libtinfo5 is still required for installation to work, but the message currently provides no indication of that.

The problem is not that Debian 10 needs libtinfo.so.5, but rather that there is no Deb 10 bindist. We use the Deb 9 bindist at the moment, which links to libtinfo.so.5. Debian 10 provides libtinfo.so.

We could fix this by using the Fedora bindist for Debian 10+, since that bindist links to libtinfo.so, instead of libtinfo.so.5. When GHC starts releasing Deb 10 bindists we would switch to using those.

I made a similar change in !107 (merged) and !108 (merged)

I think it's harmless to suggest installing libtinfo.

merged