add SYSCONFDIR variable to allow FHS-compliant builds

[Newchair2644]

This change separates the installation prefix (PREFIX) from the system configuration directory by introducing a new SYSCONFDIR variable.

Currently, the skyscraper.pro file installs configuration files under $${PREFIX}/etc/skyscraper, which can result in non-FHS-compliant paths such as /usr/etc/skyscraper. This makes it hard to package skyscraper for most distros without a patch. By separating the /etc installation prefix from the binary prefix we can build an an FHS-compliant build without a patch.

With this change

• SYSCONFDIR defaults to $${PREFIX}/etc, preserving original behavior for local builds.
• Distributors can override SYSCONFDIR to /etc (or any other desired path) without modifying the .pro file.
• Binaries can still be installed under $${PREFIX}/bin as before.

[Gemba]

Thanks. A few minor corrections.

The SYSCONFDIR should also be reflected to the preprocessor, like in the line DEFINES+=PREFIX=\\\"$$PREFIX\\\" in this pro file.
Consequently, this line should utilize the SYSCONFDIR.

With this changes I am happy to merge.

BTW: What (distro)package are you about to create?

[Newchair2644]

I just made the corrections, thanks.

I made a package for Void Linux, it builds with this patch and it works great. I will make the PR for the void package very soon but what I have so far is here: void-linux/void-packages@243c289.

[Gemba]

Thanks for putting this together. Happy to accept the follow-up PR for void Linux whenever it is ready.

[Newchair2644]

I noticed some of the CI tests were failing, because I didn't set the new SYSCONFDIR variable in the tests, so I ran them locally and corrected the tests which were failing: abstractscraper, config, getsearchnames, pegasus, and settings. I I simply added the DEFINES+=SYSCONFDIR=\\\"$$SYSCONFDIR\\\" to the respective .pro files and set the default value for SYSCONFDIR as before. I pushed my changes to my branch as a separate commit for your review: master...Newchair2644:skyscraper:master. If these changes look good should I squash the commits and you can re-merge or make a new PR? Whatever is easiest for you I am not very experienced with git.

[Gemba]

Thanks for the heads up. I was too impatient to wait for the tests to finish, it escaped me too.

Nvm and no worries :

1. Make a git format-patch bb56c1 (i.e. the changes for the testcases) on your fork. This will create some file 0001-<git commit msg>.patch
2. Then update your fork/main with Gemba/main (there is a button at github when you are on your fork)
3. make a new branch from your main: git checkout -b fix_sysconfdir_testcases (or whatever name you like)
4. apply the patch git apply 0001-*
5. add, commit and file another PR

This is from top of my head. If you are stuck it can also be I missed sth. Just shout in any case.

[Newchair2644]

Thanks a lot for the guidance, I just made the PR.