+void compute_output_file_names (void);
+
+FILE *xfopen (const char *name, const char *mode);
+int xfclose (FILE *ptr);
+
+/* Is SUFFIX ending STRING? */
+int strsuffix (const char* string, const char* suffix);
+
+/* Return a newly allocated string composed of the concatenation of
+ STRING1, and STRING2. */
+char* stringappend (const char* string1, const char* string2);