Hotfix qt plugin dir

[ddkn]

First time contributor checklist

• [x] I have read the README
• [x] I have read the CONTRIBUTING document

Contributor checklist

• [x] I have branched from the develop branch
• [x] My commits are in nice logical chunks
• [x] My contribution is fully baked and is ready to be merged as is or I have cleanly laid out what this pull request should achieve in the end

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Description

Qt cannot find plugins directory, i.e. xcb could not be found. Unless the user specifies the plugin path in the qt.conffile by the spirit binary or specifying the plugin path as an environmental variable, the application fails. Qt defaults to ${plugin_dest_dir}/plugins not ${plugin_dest_dir}/PlugIns, which is an issue for case sensitive file systems. This simple patch corrects this, for master and stable tags.

This was found on Debian/Buster, which should be a problem on any *nix system like Ubuntu.

[codecov[bot]]

Codecov Report

Merging #568 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #568   +/-   ##
=======================================
  Coverage   50.26%   50.26%           
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  Files          88       88           
  Lines       10179    10179           
=======================================
  Hits         5116     5116           
  Misses       5063     5063           

[GPMueller]

Thanks for taking the time to find a fix and create a PR :) It is actually required to be called PlugIns, not plugins, when bundling a .app on OSX, which this PR would therefore break.

However, this should be fixed with PR #565. The changes you made here are reflected there in lines 273 and 390. It would be great if you could let us know whether that PR (i.e. the improved-cmake branch) works for you or if other changes are still needed!

[ddkn]

I tried the improved-cmake branch and builds and installs as expected!

I didn't realize that OSX required PlugIns. Seems funny when default installs want a case-insensitive file system nowadays. Your branch however fixes my issues, so I am very happy!

Thanks again!

[ddkn]

Since this is not required, I can close this pull request.

Thanks again @GPMueller