#40 Linux compilation fixes for version 0.7.0

[Matthias Mailänder]

Version 0.7.0 did not compile on openSUSE Leap 15.2 so I did my best to resolve all the errors. See the patch attached. I had to create a local git repository from the tarball to create this patch as it seems you don't update the online one anymore.

[Matthias Mailänder]

See https://build.opensuse.org/request/show/859851 for an integration test.

[Hendrik Vennekate]

Thanks for reporting and sorry, my bad. I'm working with Tumbleweed, so my Qt version is more recent and while fixing some deprecation warnings, I just used what they recommended (e.g. the constructor for QSet with the begin and end iterators) without checking the docs of those methods (it appears that said constructor was introduced only in Qt 5.14).
Let me see if we can use some macros to sort this out -- or maybe just live with the deprecation warning as Qt 6 seems to be around the corner.

What was the "cannot find its libraries" change to the build scripts about? As for the build system, I have to admit that I was a little lazy there as well and possibly forgot to check the cmake build (I usually use qmake -- well, not an optimal situation to have both of them in the same project).

[Hendrik Vennekate]

Oh, and one more note -- should probably be added in one of the readme files -- the repo is at https://github.com/hvennekate/Molsketch

[Hendrik Vennekate]

Hi Matthias!
After merging your fixes, I also reworked some other aspects of the cmake-based build process.
Would you be so kind as to let me know if those changes (on the main branch of the github repo) cause any trouble on your end?

Many thanks in advance and kind regards!