this is exit code of synchronous subprocess. */
extern int synch_process_retcode;
+/* The name of the file open to get a null file, or a data sink.
+ VMS, MS-DOS, and OS/2 redefine this. */
+#ifndef NULL_DEVICE
+#define NULL_DEVICE "/dev/null"
+#endif
+
+/* A string listing the possible suffixes used for executable files,
+ separated by colons. VMS, MS-DOS, and OS/2 redefine this. */
+#ifndef EXEC_SUFFIXES
+#define EXEC_SUFFIXES ""
+#endif