cleaned up handling of specifying multiple libraries at once

[firewave]

No description provided.

[firewave]

The GUI only passes a single file to the library loading.

[chrchr-github]

Let's bikeshed about this unimportant utility function, which seems quite inefficient.

We could use a very short regex version (which also doesn't produce empty strings), or this replacement:

std::list<std::string> splitString2(const std::string& str, char sep)
{
    std::list<std::string> l;
    std::string::size_type pos = 0;
    for (;;) {
        const std::string::size_type newPos = str.find(sep, pos);
        l.push_back(str.substr(pos, newPos - pos));
        if (newPos == std::string::npos) {
            break;
        }
        pos = newPos + 1;
    }
    return l;
}

https://godbolt.org/z/85E8xGThd

[firewave]

I already a simpler version locally (which might be identical to your version) which I will add in a follow-up PR which will also extend its usage. I wanted to keep this topical and not introduce any functional non-refactoring changes.

[chrchr-github]

I see.
There still is a merge conflict.