git no longer builds on SunOS 5.10, a report

Hi all,

I've spent the entire day trying to fix the build for SunOS 5.10, as I've done a few times over the years out of sheer stubbornness, but this time I'm throwing in the towel. I figured I would at least relay what I found though, in case anyone else came looking.

First, clar.suite was generated as broken because clar-decls.h was generated as empty. Tweaking the sed one-liner in Makefile that is used to generate clar-decls.h fixed that (move the end-of-line marker outside of the capture group, `$$\)` -> `\)$$`), which I would submit as a patch, but (a) that only fixed part of the problem and (b) I'm not entirely sure why it helped. If someone else wants to apply this change, which would align the end-of-line marker placement with the start-of-line marker placement, have at it.

The next issue was that clar/sandbox.h uses mkdtemp, which I don't have here. Git has solved this in compat/mkdtemp.c via git-compat-util.h, but clar is not using it. Adding git-compat-util.h to clar/sandbox.h feels weird, but does get us further along. That change introduced banned.h into clar, which exposed the use of strncpy and localtime, both otherwise banned in git.

Including git-compat-util.h in clar/sandbox.h (bringing in mkdtemp, and replacing strncpy with strlcpy) and clar/summary.h (replacing localtime with localtime_r) leads to our next issue: a redefinition of _FILE_OFFSET_BITS, which is defined unconditionally in git-compat-util.h, because clar.c imports system headers that define it first. git-compat-util.h is meant to be included first, so, I added git-compat-util.h to the top of clar.c. That caused system includes via <wchar.h> to no longer compile due to syntax errors. This is where I gave up.

I'm sad that I can no longer build git on this old version of SunOS, and that it's the newly-imported unit-testing framework and not git itself that is preventing me from building it. Given the talk of adding rust to git, and of bumping the perl requirements to 5.26.0 (I have a system 5.8.3, and a 5.10.1 for building openssl), this moment was inevitable. On the plus side, this was the slowest platform I built git on, so perhaps I should be happy about my new free time.

Please note that this should not be read as opposition to the new unit-testing framework in any way. Building git (and curl, and gmake, and zlib, and openssl, and perl, all for git) for SunOS was a hobby for me, and not anything I personally need, and besides, it's not like my previous builds have disappeared.

The last successful build for me was 2.45.2. I've built or tried to build most versions since 1.6.6. Some of my build infrastructure was unavailable since sometime after 2.45.2, so I have not tried 2.46.x, but it lacks clar, so I expect it would build fine.

Cheers, -Alejandro