Raise the minimum CMake version to 3.10

[dimztimz]

The CMake file states 3.5 as minimal version, but 3.8 was actually minimal, see patch 47d56f2. Before that patch 3.9 was needed. This patch really fixes compatibility with 3.5.

[codecov]

Codecov Report

Merging #2523 (7c4e3b2) into devel (359542d) will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##            devel    #2523      +/-   ##
==========================================
+ Coverage   91.54%   91.56%   +0.02%     
==========================================
  Files         183      183              
  Lines        7562     7560       -2     
==========================================
  Hits         6922     6922              
+ Misses        640      638       -2     

[horenmar]

No, thanks. When I have time for Catch2 again, I am going to instead bump up the minimum required version of CMake.

[dimztimz]

Which version of Cmake do you want? My intention was to clean the file of two calls to project() inside if condition. That looks kinda hacky. Is 3.8 Acceptable?

[dimztimz]

This patch does two things:

1. Cleans some code, looks better
2. Actually fixes a small bug. The bug is that the call to cmake_minimum_version currently is incorrect.

[horenmar]

Do you have good reason for wanting to bump it up to 3.8 specifically? I looked at default packages in LTS ubuntu as a benchmark, bionic has 3.10.2, focal 3.16.3. Based on this I would target 3.16 on my own, but I am willing to hear arguments for other versions.

The cleanup makes sense, if it is still needed after the bump. I did the fastest thing I could when making the change.

[dimztimz]

Well, I will list useful features that can be used.

• v3.6 Adds support for Clang-tidy static analysis
• v3.8 Adds support for C++17, support for Cpplint static analysis
• v3.9 Improves command project()
• v3.10 Adds support for Cppcheck static analysis.
• v3.12 Improves command project().
• v3.14 Simplifies calls to command install().

Personally, I'd bump it to 3.8 now, 3.10 in couple of months and I'd go above 3.10 when Ubuntu 18.04 goes out of support (precisely, in Extended Security Maintenance).

[horenmar]

Ok, I am willing to keep it at 3.10 for now.

[dimztimz]

I changed the PR so it raises the CMake minimum version to 3.10, and also it cleans the calls to project().

[horenmar]

Thanks.