[PATCH] fix C4204 errors while building swig-py with Python 3.9 on Windows

[Jun Omae]

Hi,

I tried to build swig-py with Python 3.9 on Windows, however get the following 
errors:

[[[
C:\usr\apps\python39\include\cpython\abstract.h(205,1): error C4204: 
nonstandard extension used: non-constant aggregate initializer 
[C:\usr\src\subversion\trunk-py39\build\win32\vcnet-vcproj\libsvn_swig_py.vcxproj]
C:\usr\apps\python39\include\cpython\abstract.h(250,1): error C4204: 
nonstandard extension used: non-constant aggregate initializer 
[C:\usr\src\subversion\trunk-py39\build\win32\vcnet-vcproj\libsvn_swig_py.vcxproj]
]]]

The error was raised from the line 205 in cpython/abstract.h in Python 3.9:

[[[
  202 static inline PyObject *
  203 PyObject_CallMethodOneArg(PyObject *self, PyObject *name, PyObject *arg)
  204 {

205     PyObject *args[2] = {self, arg};

  206
]]]

The attached patch adds #pragma warning to make C4204 a warning instead of an
error only on building swig-py with Visual Studio.

--
Jun Omae <jun6...@gmail.com> (大前 潤)

Fix C4204 errors while building swig-py with Python 3.9 on Windows.

* subversion/bindings/swig/include/svn_global.swg:
  Add #pragma to make C4204 a warning instead of an errors from Python.h
  in Python 3.9 with Visual Studio.
* subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.c: Ditto.


Index: subversion/bindings/swig/include/svn_global.swg
===================================================================
--- subversion/bindings/swig/include/svn_global.swg     (revision 1883337)
+++ subversion/bindings/swig/include/svn_global.swg     (working copy)
@@ -34,6 +34,11 @@
 #ifdef SWIGPYTHON
 %begin %{
 #define SWIG_PYTHON_STRICT_BYTE_CHAR
+#if defined(_MSC_VER)
+/* Prevent "non-constant aggregate initializer" errors from Python.h in
+ * Python 3.9 */
+# pragma warning(default : 4204)
+#endif
 %}
 #endif
 
Index: subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.c
===================================================================
--- subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.c        
(revision 1883337)
+++ subversion/bindings/swig/python/libsvn_swig_py/swigutil_py.c        
(working copy)
@@ -26,6 +26,12 @@
 /* Avoid deprecation warnings about PY_SSIZE_T_CLEAN since Python 3.8 */
 #define PY_SSIZE_T_CLEAN
 
+#if defined(_MSC_VER)
+/* Prevent "non-constant aggregate initializer" errors from Python.h in
+ * Python 3.9 */
+# pragma warning(default : 4204)
+#endif
+
 #include <Python.h>