Support old PHP versions

[phfroidmont]

As suggested in #240, adds support for all stable php versions from https://github.com/fossar/nix-phps

[DavHau]

Thanks for that.
According to the readme of nix-phps: There is also a php package which is the alias of the default PHP version in Nixpkgs.
Can we ensure that the nixpkgs php remains the preferred choice over the other php packages?

@tinybeachthor pinging you in case you'd like tor review this.

[DavHau]

Suggested change

	phpPackages = l.attrValues inputs.phps.packages.x86_64-linux;
	phpPackages = l.attrValues inputs.phps.packages.x86_64-linux;
	phpPackages = l.attrValues (import inputs.phps).packages.x86_64-linux;

[phfroidmont]

For my own understanding, what does import do here?

[DavHau]

Instead of treating inputs.php like a flake, it treats it as a path and imports it. Currently we have a failing CI tests, because under some circumstances inputs.php is a path and not a flake. This is buggy behavior in our backward compat mechanism which I don't intend to fix anymore in favor of the upcoming v1 API changes.

[DavHau]

Suggested change

	phpPackages = l.attrValues inputs.phps.packages.x86_64-linux;
	phpPackages = l.attrValues inputs.phps.packages.x86_64-linux;
	phpPackages = l.attrValues (import inputs.phps).packages.x86_64-linux;

[tinybeachthor]

Probably does not make much difference, maybe passing system attribute here instead of hard-coding x86_64-linux.

[phfroidmont]

php being first on the list it will be the first considered if I'm not mistaken.
Still, I can add a bit of logic to ensure it is always considered first, no matter the ordering of the list.

[aszenz]

Will php still work with the V1 api?