Using __has_include to detect header files

Author: aisk

PC/pyconfig.h

@@ -672,7 +672,11 @@ Py_NO_ENABLE_SHARED to find out.  Also support MS_NO_COREDLL for b/w compat */
 /* #define HAVE_SYS_UN_H 1 */
 
 /* Define if you have the <afunix.h> header file.  */
-#define HAVE_AFUNIX_H 1
+#if defined(__has_include) && __has_include(<afunix.h>)
+    #define HAVE_AFUNIX_H 1
+#else
+    #define HAVE_AFUNIX_H 0
+#endif
 
 /* Define if you have the <sys/utime.h> header file.  */
 /* #define HAVE_SYS_UTIME_H 1 */