build-support/php: reorganize files

Pave the way for having multiple versions in the future

pkgs/build-support/php/build-composer-project.nix pkgs/build-support/php/builders/v1/build-composer-project.nix

···
     let
       phpDrv = finalAttrs.php or php;
       composer = finalAttrs.composer or phpDrv.packages.composer;
-      composer-local-repo-plugin = callPackage ./pkgs/composer-local-repo-plugin.nix { };
+      composer-local-repo-plugin = callPackage ../../pkgs/composer-local-repo-plugin.nix { };
     in
     {
       composerLock = previousAttrs.composerLock or null;

pkgs/build-support/php/build-composer-repository.nix pkgs/build-support/php/builders/v1/build-composer-repository.nix

···
     let
       phpDrv = finalAttrs.php or php;
       composer = finalAttrs.composer or phpDrv.packages.composer;
-      composer-local-repo-plugin = callPackage ./pkgs/composer-local-repo-plugin.nix { };
+      composer-local-repo-plugin = callPackage ../../pkgs/composer-local-repo-plugin.nix { };
     in
     assert (lib.assertMsg (previousAttrs ? src) "mkComposerRepository expects src argument.");
     assert (

pkgs/build-support/php/builders/default.nix

···
+{ callPackage, callPackages, ... }:
+{
+  v1 = {
+    buildComposerProject = callPackage ./v1/build-composer-project.nix { };
+    mkComposerRepository = callPackage ./v1/build-composer-repository.nix { };
+    composerHooks = callPackages ./v1/hooks { };
+  };
+}

pkgs/top-level/php-packages.nix

···
 
 lib.makeScope pkgs.newScope (self: let
   inherit (self) buildPecl callPackage mkExtension php;
+
+  builders = import ../build-support/php/builders {
+    inherit callPackages callPackage buildPecl;
+  };
 in {
   buildPecl = callPackage ../build-support/php/build-pecl.nix {
     php = php.unwrapped;
   };
 
-  composerHooks = callPackages ../build-support/php/hooks { };
-
-  mkComposerRepository = callPackage ../build-support/php/build-composer-repository.nix { };
-  buildComposerProject = callPackage ../build-support/php/build-composer-project.nix { };
+  inherit (builders.v1) buildComposerProject composerHooks mkComposerRepository;
 
   # Wrap mkDerivation to prepend pname with "php-" to make names consistent
   # with how buildPecl does it and make the file easier to overview.