Minor fixes that prevent from building

[xypp3]

• Include qobject.h in ifcdef.cpp in the ifc library
• Remove warings from export_layout_dialog.cpp by adding in a string literal into the constructor function

[CLAassistant]

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[what-the-diff]

Making Things Better! 🎉👏

Fantastic work team! Some neat updates have been pushed and I'm here to take you through the magic behind the curtain in a jargon-free way!

• A Tiny, Mighty Change in export_layout_dialog.cpp! 😃
  A small yet powerful update has been made in our code. Instead of using a 'QString' that was empty, now we have an '"empty string literal"'. In the simplest words, just think of it like cleaning and freeing up a tiny room (QString) which was empty, for more important tasks. Bravo for the clean-up work, team! ✨

• Inviting a New Friend to ifdef.cpp, say hello to qobject.h 🎁
  Another file called qobject.h has been invited into ifdef.cpp. It's like inviting a new person to join the party (our code). This addition provides us with more abilities that may help us achieve our goals faster! Excellent job team on this successful invitation! 🎈

And that's the roundup. Keep up the amazing job team, your small changes make our project shine brighter! 😊🚀

[xypp3]

Sorry I made the PR to the wrong repo