Install fails on Ubuntu 18.04.3
Just tried to install nim via choosenim as suggested on https://nim-lang.org/install_unix.html

This is the result: https://gist.github.com/winks/7332db98eceb0678cffb95bf7d3ef0b8

I only snipped all the `... Hint: xxx [Processing ]` lines

What I installed and did **not** help after reading https://github.com/dom96/choosenim#dependencies :

```
gcc-7-base:amd64                7.4.0-1ubuntu1~18.04.1
zlib1g-dev:amd64                1:1.2.11.dfsg-0ubuntu2
libssl-dev:amd64                1.1.1-1ubuntu2.1~18.04.5
build-essential (metapackage)
```

Not a real problem, the prebuilt binaries work fine. But if it's just a doc issue of deps this should probably be fixed on `install_unix.html` as beginners (this guy) are likely to try this.