[Development] Did we have to remove cmake's qt5_use_modules?

[Thiago Macieira]

Commit 02ed1b36daebed5f3997bb676cf5e818c0db9d3c was

    Remove CMake code for CMake < 3.1
    
    This removes the following functions from Qt5CoreMacros:
    - qt5_use_modules(...)

Which follows 2013's d9ea4bb1441534cfb9253303ac258951dfcc4d9e

    Mark qt5_use_modules as obsolete.
    
    Forward-port of cb7f32f5b861fe115fa71f64500a5cbb0b643f1b (Mark
    qt4_use_modules and qt4_automoc as obsolete., 2013-07-04) from
    cmake.git.

But it appears that in the 5 years since we deprecated it, people have not 
stopped using it. Did we have to remove it? Or should we have kept 
compatibility until Qt 6?

Just look at the failures in
https://build.opensuse.org/project/monitor/openSUSE:Factory?
arch_x86_64=1&defaults=0&failed=1&repo_standard=1

The majority of them are caused by the Qt 5.11 update, a great number of which 
are the cmake update (the rest are indirect header dependency and are easy to 
fix).
-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center