gh-98705: Fix AIX build by undefining __bool__ in C (#98768)

Author: ayappanec

Include/pyport.h

@@ -726,4 +726,10 @@ extern char * _getpty(int *, int, mode_t, int);
 #  endif
 #endif
 
+
+/* AIX has __bool__ redefined in it's system header file. */
+#if defined(_AIX) && defined(__bool__)
+#undef __bool__
+#endif
+
 #endif /* Py_PYPORT_H */

Misc/NEWS.d/next/Build/2022-10-27-09-57-12.gh-issue-98705.H11XmR.rst

@@ -0,0 +1,2 @@
+``__bool__`` is defined in AIX system header files which breaks the build in
+AIX, so undefine it.