How to cross-build for a different Linux version (w/ Qt Creator)?

[Hes]

Hello everyone,
I recently upgraded my development system from Linux Mint 12 (which essentially is an Ubuntu 11.10) to the current LTS release of Ubuntu (14.04). This also upgraded Qt from 4.7.4 to 4.8.5. Now, my projects don't use any new features and thus compile fine on either system. But if I want an executable that runs on the older system, I have to compile it on the older system - not because of Qt itself, but because a binary compiled on the Ubuntu 14.04 requires a newer version of the glibc than what is availabe for the old system.

I have a number of these old systems for which I want to compile the software, but as I need tools from the new devel system during development (not for compilation itself, but for testing certain things), I constantly have to reboot from the old to the new to the old system, so that I can develop on the new one, and then after first tests move the source to the old one, compile and run it there.

This is very inconvenient. So my question in short is: is there a way to create a toolchain or add-on to the development environment on the new system, so that I can cross-compile there for the old Ubuntu 11.10. I have a second machine where I can run the binary with the old system (that's the actual target machine for the program), but that machine has no development tools whatsoever, plus it is way too slow to compile on there (slow Intel Atom CPU, small memory).

So, it there a way to cross-compile Qt projects on Ubuntu 14.04 for Ubuntu 11.10? Any help is appreciated.

Best regards, Michael