Minimal compiler versions

[edgarcosta]

In #2054 we noted that GCC 8 is no longer supported.
What is the minimal version required to build flint?
What about clang?
Or better, what features do we need?

Given this, where should we add this to the documentation?

Can we add this to the configure?

[edgarcosta]

Also, on the same line of thought, should we try to consolidate INSTALL.md and doc/source/building.rst ?
At first pass, a symlink could do.

[albinahlback]

For inclusions of headers, we require that GNU compatible compilers is able to utilize attributes and macros from flint.h like FLINT_FORCE_INLINE. For compiling FLINT, we also require (but we strictly would not need to require) that GNU compatible compilers have all the pragmas we utilize. In the case of #2054, this is dangling pointer warnings.

We can still solve the issue by pushing something like

#if defined(__GNUC__) && __GNUC__ > SOME_NUMBER

and this goes for everything. We could support GCC 3 if we'd like to.

However, as a general note, I do not like the idea of having to support old compilers. If you build the newest release of a package, I think it is reasonable to expect that you have software that is somewhat new (say, at most two years old).

[albinahlback]

But, it would be good to document or clarify in the documentation.

[fredrik-johansson]

However, as a general note, I do not like the idea of having to support old compilers. If you build the newest release of a package, I think it is reasonable to expect that you have software that is somewhat new (say, at most two years old).

Though it's not clear that two years is a reasonable cutoff. Lots of people are on LTS distros way older than that, and there are institutional HPC clusters where the installed GCC version dates back to the geologic era of the volcanic sediments under the ground of the building where the computers are housed.

In my experience new compiler versions are more problematic anyway. The old versions have a known list of limitations; new versions always introduce creative new issues :-)

[edgarcosta]

@albinahlback let me know if there is anything I can help you with this.

In particular, there are people that keep systems in the Jurassic era to make it easy to compile binaries against very old versions of glibc, and I would like to get them to compile flint 🙃

[albinahlback]

Yeah yeah, I'll be on it after fixing Nemo!