feat: install examples for top level builds

[Scrumplex]

What does this change do?

This change installs built examples as binaries.
This might be useful for distribution packagers to provide these example programs in their packages.

Is it related to an existing bug report or feature request?

N/A

Pre-merge checklist

• I've read CONTRIBUTING.md
• I've rebased my changes against the current HEAD of origin/master (if necessary)
• I've added new test cases to verify my change
• I've regenerated toml.hpp (how-to)
• I've updated any affected documentation
• I've rebuilt and run the tests with at least one of:
  • Clang 8 or higher
  • GCC 8 or higher
  • MSVC 19.20 (Visual Studio 2019) or higher
• I've added my name to the list of contributors in README.md

[marzer]

Hmmmn, I think this should also have an option to control it, and be off by default. I know I personally have never wanted the INSTALL target of a project to install examples/demos/tests, et cetera, when I was doing a system build; I imagine many others are the same.

[Scrumplex]

I would argue that setting -Dbuild_examples=true would only make sense in the context of a system build if those examples are also installed. Otherwise, it doesn't really make much sense to build those examples when your intent is to package the software for a system build.

[marzer]

I don't want example binaries to install by default. This is standard practice.

would only make sense in the context of a system build if those examples are also installed

I'm saying people shouldn't be surprised by unexpected example binaries being installed if they try to install the lib system-wide, and it appears your change would cause that.

Never mind, see below 😅

[marzer]

Oh, wait a minute, I get what you're saying now. People have to opt-in to building the examples to begin with, heh. Sorry, brain-fart. Yeah this makes sense.

[Scrumplex]

Oh, I didn't see your comment before pushing. Lemme reset back ^^

Edit: Note to self: Check PR comments before running gh pr ready --undo ^^

[marzer]

🎉 cheers :)