* outfilename - name of output file
* did_outfilename - whether outfilename was explicitly set
* prefix - the prefix used for externally visible names ("yy" by default)
+ * do_stdinit - whether to initialize yyin/yyout to stdin/stdout
* use_stdout - the -t flag
* input_files - array holding names of input files
* num_input_files - size of input_files array
extern char *infilename, *outfilename;
extern int did_outfilename;
extern char *prefix;
-extern int use_stdout;
+extern int do_stdinit, use_stdout;
extern char **input_files;
extern int num_input_files;
extern char *program_name;