bash-completion: add subport for bash 3.2 compatible version

[mohd-akram (Mohamed Akram)]

It would be nice to have a subport which supports the default macOS bash. I prefer to use the default bash to make sure scripts work on other systems. Homebrew currently does this by having two separate formulae, bash-completion & bash-completion@2. The last version compatible with bash 3.2 is bash-completion 1.3.

[raimue (Rainer Müller)]

As a side note, you can still test scripts with /bin/bash regardless of the bash version you use as interactive shell. You are not forced to keep using bash 3.2 for this reason.

bash-completion 1.3 is old and unmaintained. I see that it might be useful for some, therefore I am happy to apply a patch to provide a subport such as bash-completion-legacy or bash32-completion. However, personally I see no point in providing ports without an upstream source that is actively working on bugfixes and improvements and will not work on this.

[mohd-akram (Mohamed Akram)]

With Apple essentially ​deprecating bash in macOS Catalina, there won't be much need for this.