Append custom parameter to the end of sys.argv

Author: radarhere

_custom_build/backend.py

@@ -11,14 +11,12 @@
 class _CustomBuildMetaBackend(backend_class):
     def run_setup(self, setup_script="setup.py"):
         if self.config_settings:
-            params = []
             for key, values in self.config_settings.items():
                 if not isinstance(values, list):
                     values = [values]
                 for value in values:
-                    params.append(f"--pillow-configuration={key}={value}")
+                    sys.argv.append(f"--pillow-configuration={key}={value}")
 
-            sys.argv = sys.argv[:1] + params + sys.argv[1:]
         return super().run_setup(setup_script)
 
     def build_wheel(

setup.py

@@ -998,10 +998,9 @@ def debug_build():
 
 
 # parse configuration from _custom_build/backend.py
-while len(sys.argv[1]) >= 2 and sys.argv[1].startswith("--pillow-configuration="):
-    _, key, value = sys.argv[1].split("=", 2)
+while sys.argv[-1].startswith("--pillow-configuration="):
+    _, key, value = sys.argv.pop().split("=", 2)
     configuration.setdefault(key, []).append(value)
-    del sys.argv[1]
 
 try:
     setup(