Update backend.py

Author: mayeut

_build_backend/backend.py

@@ -108,7 +108,6 @@ def _bootstrap_build(temp_path: str, config_settings: dict[str, list[str] | str]
         msg = f"Invalid sha256 for {archive_url!r}. Expected {archive_sha256!r}, got {sha256!r}"
         raise ValueError(msg)
 
-    prefix_path = temp_path_ / "cmake-install"
     if os.name == "posix":
         assert archive_name.endswith(".tar.gz")
         tar_filter_kwargs = {"filter": "tar"} if hasattr(tarfile, "tar_filter") else {}
@@ -119,6 +118,8 @@ def _bootstrap_build(temp_path: str, config_settings: dict[str, list[str] | str]
         parallel = max(0, int(parallel_str) if parallel_str.isdigit() else 1) or os.cpu_count() or 1
 
         bootstrap_path = next(temp_path_.glob("cmake-*/bootstrap"))
+        prefix_path = temp_path_ / "cmake-install"
+        cmake_path = prefix_path / "bin" / "cmake"
         bootstrap_args = [f"--prefix={prefix_path}", "--no-qt-gui", "--no-debugger", "--parallel={parallel}"]
         previous_cwd = Path().absolute()
         os.chdir(bootstrap_path.parent)
@@ -131,9 +132,10 @@ def _bootstrap_build(temp_path: str, config_settings: dict[str, list[str] | str]
     else:
         assert archive_name.endswith(".zip")
         with zipfile.ZipFile(archive_path) as zip_:
-            zip_.extractall(path=prefix_path)
+            zip_.extractall(path=temp_path_)
+        cmake_path = next(temp_path_.glob("cmake-*/bin/cmake"))
 
-    return str(prefix_path / "bin" / "cmake")
+    return str(cmake_path)
 
 
 def build_wheel(