Merge pull request #16417 from ericsagnes/fix/php-platform

php: add meta.platforms

pkgs/development/interpreters/php/default.nix

···
       meta = with stdenv.lib; {
         description = "An HTML-embedded scripting language";
         homepage = http://www.php.net/;
-        license = stdenv.lib.licenses.php301;
+        license = licenses.php301;
         maintainers = with maintainers; [ globin ];
+        platforms = platforms.all;
       };
 
       patches = if !php7 then [ ./fix-paths.patch ] else [ ./fix-paths-php7.patch ];