Compile Ruby < 3.1 on Arch Linux

[FranklinYu]

It’s well known that Ruby doesn’t support OpenSSL 3 until Ruby 3.1 (it doesn’t intend to backport the support to Ruby 3.0), and the default OpenSSL version of Arch Linux is already OpenSSL 3, so we need to configure Ruby to use the legacy OpenSSL 1.1.

I’m using the openssl-1.1 package, which puts headers in /usr/include/openssl-1.1/, and libraries in /usr/lib/openssl-1.1/, so we cannot directly use --with-openssl-dir. There are two potential workarounds:

1. We can create a new directory, with includes and lib being symbolic links to the right directory.
2. We can use --with-openssl-config=my-command.

I chose the second one. I created a shim:

#!/bin/sh

PKG_CONFIG_PATH=/usr/lib/openssl-1.1/pkgconfig/ pkg-config "$@" openssl

I made it executable (via chmod), and put it on my disk (let’s say /tmp/openssl-config). Then I built Ruby 3.0 with

ruby-install ruby-3.0 -- --with-openssl-config=/tmp/openssl-config

Ruby 2.7 can be built in the same way.