PYTHON_EXECUTABLE -> Python_EXECUTABLE

The environment variable name in cmake is spelled a bit strangely (Python_EXECUTABLE) but the extensions.py script spelled it PYTHON_EXECUTABLE. This was causing nlopt not to build on my macOS box.

This commit fixes that environment variable name and now it builds on my arm Mac running Ventura.

Author: khwilson

extensions.py

@@ -51,7 +51,7 @@ def build_extension(self, ext: Extension):
             "cmake",
             "-LAH",
             f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY={_ed}",
-            f"-DPYTHON_EXECUTABLE={sys.executable}",
+            f"-DPython_EXECUTABLE={sys.executable}",
             "-DNLOPT_GUILE=OFF",
             "-DNLOPT_MATLAB=OFF",
             "-DNLOPT_OCTAVE=OFF",