build-system: renpy: Drop reliance on python-build-system.

* guix/build/renpy-build-system.scm (enable-bytecode-determinism): New
variable.
(%standard-phases): Replace python:enable-bytecode-determinism with
own variant.
* guix/build-system/renpy.scm (%renpy-build-system-modules):
Drop (guix build python-build-system).

Fixes: guix/guix#7426 (“Migrate `renpy-build-system' to pyproject”)

guix/build-system/renpy.scm

@@ -44,7 +44,6 @@
 (define %renpy-build-system-modules
   ;; Build-side modules imported by default.
   `((guix build renpy-build-system)
-    (guix build python-build-system)
     ,@%default-gnu-imported-modules))
 
 (define* (lower name

guix/build/renpy-build-system.scm

@@ -18,7 +18,6 @@
 
 (define-module (guix build renpy-build-system)
   #:use-module ((guix build gnu-build-system) #:prefix gnu:)
-  #:use-module ((guix build python-build-system) #:prefix python:)
   #:use-module (guix build utils)
   #:use-module (ice-9 match)
   #:use-module (ice-9 ftw)
@@ -28,6 +27,12 @@
   #:export (%standard-phases
             renpy-build))
 
+(define* (enable-bytecode-determinism #:rest _)
+  "Improve determinism of pyc and rpyc files."
+  ;; Same reasoning as in pyproject-build-system, see there…
+  (setenv "PYTHONHASHSEED" "0")
+  (setenv "PYTHONDONTWRITEBYTECODE" "1"))
+
 (define* (build #:key game #:allow-other-keys)
   (for-each make-file-writable
             (find-files game (lambda (pred stat)
@@ -96,7 +101,7 @@
 (define %standard-phases
   (modify-phases gnu:%standard-phases
     (add-after 'unpack 'enable-bytecode-determinism
-      (assoc-ref python:%standard-phases 'enable-bytecode-determinism))
+      enable-bytecode-determinism)
     (delete 'bootstrap)
     (delete 'configure)
     (replace 'build build)