Be more explicit about C++ version requierments.

[bcsgh]

Description of the Change

Prompted by #295

Release Notes

• Include the minimum C++ version in README.md
• Make any use of httpserver.hpp check the C++ version.

[etr]

We might also use: https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_17.html.

What do you think?

[bcsgh]

Seems that's already being done:
https://github.com/etr/libhttpserver/blob/master/configure.ac#L47

Also, will that give a clean error to someone who builds libhttpserver using its build system and then attempts to build their own code using C++14 and link with the .a?

Lastly, I at least don't use the autoconf build at all (I use Bazel). Autoconf is very much a pain to get a hermetic build out of (it seems to assume that the configuration of my workstation is in any way relevant to how to build the library) and doesn't integrate well with everything else I'm using.

[etr]

Seems that's already being done: https://github.com/etr/libhttpserver/blob/master/configure.ac#L47

Also, will that give a clean error to someone who builds libhttpserver using its build system and then attempts to build their own code using C++14 and link with the .a?

Great. I did not mean it as a substitution to what you have here, though, because it won't support you beyond the compilation of the library itself.

Lastly, I at least don't use the autoconf build at all (I use Bazel). Autoconf is very much a pain to get a hermetic build out of (it seems to assume that the configuration of my workstation is in any way relevant to how to build the library) and doesn't integrate well with everything else I'm using.

To be fair, what I should be doing is uploading the output of make dist. In theory, you should have to run automake/autoconf at all.

[bcsgh]

To be fair, what I should be doing is uploading the output of make dist. In theory, you should have to run automake/autoconf at all.

I'm of the "always build everything from source" school of thought. Which incidentally allows you to totally avoids the question of what set of CPU/OS/etc. to generate releases for; you'll never get enough options to make people happy, so just make sure building for their own personal snowflake is fast and easy.