Add FreeBSD terminfo location

[Thefrank]

• terminfo under FreeBSD no longer uses a hashed database but instead uses the more common "directory tree" style.
• This fixes like 1 failing runtime test for System.Console under FreeBSD.
• Please install terminfo-db via pkg before building under FreeBSD. ncurses no longer covers this.

resolves: #23653

[ghost]

Tagging subscribers to this area: @dotnet/area-system-console
See info in area-owners.md if you want to be subscribed.

Issue Details

---

• terminfo under FreeBSD no longer uses a hashed database but instead uses the more common "directory tree" style.
• This fixes like 1 failing runtime test for System.Console under FreeBSD.
• Please install terminfo-db via pkg before building under FreeBSD. ncurses not longer covers this.

Author:	Thefrank
Assignees:	-
Labels:	area-System.Console
Milestone:	-

[Thefrank]

Long version:
The terminfo database under FreeBSD was built as a hashed db. To get a usable terminfo that runtime could use would require either a) coding a unique solution specific to a hashed terminfo.db or b) requiring those that wanting support to both make the one line code in this pull request and download the FreeBSD ports tree, make the required changes to the Makefile for ncurses, and finally build ncurses with said changes. Thankfully, changes in circumstance at the beginning of the year mean that the ncurses port (and pkg) broke off the terminfo-db part as a separate install and that now uses a directory tree which is exactly what TermInfo.cs is looking for. This was mentioned and tested working in the issue linked above but it appears that the directory path was never actually added to TermInfo.cs.

Even longer version as issue: This has been a long standing issue under FreeBSD.

CC @wfurt

[am11]

Thanks Frank! I once started writing code for hasheddb build never finished it (mainly due to the lack of sufficient documentation on the initialization step, which I couldn't find).

* Please install `terminfo-db` via `pkg` before building under FreeBSD. `ncurses` not longer covers this.

Could you please add __FreeBSDPackages+=" terminfo-db" after https://github.com/dotnet/arcade/blob/0f496578b39793650160aa8a1a0e26883bf804fa/eng/common/cross/build-rootfs.sh#L70, so we get the CI build docker also aligned? (the next rebuild of dotnet-docker-prereqs will automagically pick it up).

[Thefrank]

@am11 Those docker images are another thing I need to look over (e.g., EOL FreeBSD versions and use of built in LLVM) but I will add that package to any pull request I make there.

[Thefrank]

I made an edit to the original post as I forgot to link this PR to the issue it addresses. It is the same one mentioned in my second comment under "Even longer version"

[adamsitnik]

LGTM, thank you @Thefrank

as soon as @wfurt approves it, we are going to merge it and hopefully include it as part of .NET 6

[wfurt]

LGTM