2022.06.05 14:06 "Re: [Tiff] Upgrade of CI image", by Greg Troxel

Libtiff now absolutely requires a C99 compiler and run-time library. It is able to compile and run under Microsoft Windows and POSIX-compliant OSs.

Thanks; I updated the pkgsrc entry to require C99 (not that anyone uses pkgsrc with pre-C99 compilers).

Most issues encountered are with newer verions of compilers due to introducing new warnings/optimizations and are not related to the underlying OS.

In other projects, problems arise when someone relies on a new compiler feature beyond the documented language standard, or uses a linux-only header.

Introducing Ubuntu 22.04 LTS as a test environment seems quite valuable to me due to updated compilation environments and a much newer GNU C library. Continuing testing on Ubuntu 20.04 or 18.04 does not seem very valuable to me since failures there are unlikely. It is more useful to test on non-Linux OSs than older vintages of Linux-based OSs.

We are more likely to encounter issues due to CMake on older OS versions than we are with the compiler/headers/libraries.

That's fair enough if there are some other older systems in CI. Certainly doesn't need to be Ubuntu. I didn't realize there was coverage for oldest-sane-gcc.