fix: Escape paths with spaces in include list from --includes

Author: Markus Bauer

pybind11/__main__.py

@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 import argparse
+import shlex
 import sys
 import sysconfig
 
@@ -22,7 +23,7 @@ def print_includes() -> None:
         if d and d not in unique_dirs:
             unique_dirs.append(d)
 
-    print(" ".join("-I" + d for d in unique_dirs))
+    print(" ".join(shlex.quote("-I" + d) for d in unique_dirs))
 
 
 def main() -> None: