use a trick to get_config_var as before

Author: Chongkai Zhu

cpython-unix/build-cpython.sh

@@ -1031,6 +1031,7 @@ extension_suffixes.append(".abi3.so")
 
 extension_suffixes.append(".so")
 
+libpl_path = sysconfig.get_config_var("LIBPL")
 metadata = {
     "python_abi_tag": sys.abiflags,
     "python_implementation_cache_tag": sys.implementation.cache_tag,
@@ -1050,7 +1051,7 @@ metadata = {
     "python_paths_abstract": sysconfig.get_paths(expand=False),
     "python_exe": "install/bin/python%s%s" % (sysconfig.get_python_version(), sys.abiflags),
     "python_major_minor_version": sysconfig.get_python_version(),
-    "python_stdlib_platform_config": sysconfig.get_config_var("LIBPL"),
+    "python_stdlib_platform_config": libpl_path[libpl_path.find("install"):],
     "python_config_vars": {k: str(v) for k, v in sysconfig.get_config_vars().items()},
 }
 

cpython-unix/build.py

@@ -682,7 +682,8 @@ def python_build_info(
         }
 
         if info.get("build-mode") == "shared":
-            shared_dir = extra_metadata["python_config_vars"]["DESTSHARED"].strip("/")
+            shared_dir = extra_metadata["python_config_vars"]["DESTSHARED"]
+            shared_dir = shared_dir[shared_dir.find("install"):]
             extension_suffix = extra_metadata["python_config_vars"]["EXT_SUFFIX"]
             entry["shared_lib"] = "%s/%s%s" % (shared_dir, extension, extension_suffix)