Make a guess:

**	variables defined in |pxfile.c|. Consult also the documentation
**	of this file for details.
**
**	This header file automatically includes |bibtool.h| and |<stdio.h>|.
**
******************************************************************************/

#include <stdio.h>

extern char * px_filename;

extern FILE * px_fopen(
#ifdef __STDC__
	char  * name,
	char  * mode,
	char  **pattern,
	char  **path,
	int   (*show)()
#endif
	);

extern char **px_s2p(
#ifdef __STDC__
	char  * s,
	int   sep
#endif
	);