Keep non-windows prefix overwrite quirk on a venv's base_prefix

Signed-off-by: Filipe Laíns <[email protected]>

Author: FFY00

Modules/getpath.py

@@ -764,8 +764,8 @@ def search_up(prefix, *landmarks, test=isfile):
     if not venv_prefix:
         prefix = config.get('prefix') or PREFIX
         exec_prefix = config.get('exec_prefix') or EXEC_PREFIX or prefix
-    base_prefix = config.get('base_prefix') or prefix
-    base_exec_prefix = config.get('base_exec_prefix') or base_prefix
+    base_prefix = config.get('base_prefix') or PREFIX
+    base_exec_prefix = config.get('base_exec_prefix') or EXEC_PREFIX or base_prefix
 
 
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