qt5-base: Don't use new-ish kernels

[drbenmorgan]

Running an ubuntu 18 container on a CentOS 7 system warned about libQt5Core.so not being found. Binaries were checked for correct RUNPATHs and found to be o.k. Other Qt libraries were found and loaded without issue. Probable cause found to be Qt encoding kernel ABI into library (and thus container shared kernel not supporting this) per report here:

https://github.com/NixOS/nixpkgs/pull/40577

Use same set of arguments in that patch to build binaries with compatibility for older kernels.

• [x] Have you followed the guidelines for contributing?
• [x] Have you checked that there aren't other open pull requests for the same formula update/change?
• [x] Have you built your formula locally with brew install --build-from-source <formula>, where <formula> is the name of the formula you're submitting?
• [x] Does your build pass brew audit --strict <formula> (after doing brew install <formula>)?

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