Also allow the -Wzero-as-null-pointer-constant warning

Author: encukou

Lib/test/setup_testcppext.py

@@ -35,9 +35,6 @@ def main():
         name = '_testcpp11ext'
 
     cppflags = [*CPPFLAGS, f'-std={std}']
-    if std == 'c++11':
-        # Warn when using NULL rather than _Py_NULL in static inline functions
-        cppflags.append('-Wzero-as-null-pointer-constant')
 
     cpp_ext = Extension(
         name,

Misc/NEWS.d/next/C API/2022-07-12-17-39-32.gh-issue-94731.9CPJNU.rst

@@ -1,3 +1,3 @@
 Python again uses C-style casts for most casting operations when compiled
 with C++. This may trigger compiler warnings, if they are enabled with e.g.
-``g++ -Wold-style-cast``.
+``-Wold-style-cast `` or ``-Wzero-as-null-pointer-constant`` options for ``g++``.