-extern int copy OF((int in, int out));
-extern ulg updcrc OF((uch *s, unsigned n));
-extern void clear_bufs OF((void));
-extern int fill_inbuf OF((int eof_ok));
-extern void flush_outbuf OF((void));
-extern void flush_window OF((void));
-extern void write_buf OF((int fd, voidp buf, unsigned cnt));
-extern int read_buffer OF((int fd, voidp buf, unsigned int cnt));
-extern char *strlwr OF((char *s));
-extern char *gzip_base_name OF((char *fname));
-extern int xunlink OF((char *fname));
-extern void make_simple_name OF((char *name));
-extern char *add_envopt OF((int *argcp, char ***argvp, char const *env));
-extern void gzip_error OF((char const *m)) ATTRIBUTE_NORETURN;
-extern void xalloc_die OF((void)) ATTRIBUTE_NORETURN;
-extern void warning OF((char const *m));
-extern void read_error OF((void)) ATTRIBUTE_NORETURN;
-extern void write_error OF((void)) ATTRIBUTE_NORETURN;
-extern void display_ratio OF((off_t num, off_t den, FILE *file));
-extern void fprint_off OF((FILE *, off_t, int));
+extern int copy (int in, int out);
+extern ulg updcrc (uch *s, unsigned n);
+extern void clear_bufs (void);
+extern int fill_inbuf (int eof_ok);
+extern void flush_outbuf (void);
+extern void flush_window (void);
+extern void write_buf (int fd, voidp buf, unsigned cnt);
+extern int read_buffer (int fd, voidp buf, unsigned int cnt);
+extern char *strlwr (char *s);
+extern char *gzip_base_name (char *fname) _GL_ATTRIBUTE_PURE;
+extern int xunlink (char *fname);
+extern void make_simple_name (char *name);
+extern char *add_envopt (int *argcp, char ***argvp, char const *env);
+extern void gzip_error (char const *m) ATTRIBUTE_NORETURN;
+extern void xalloc_die (void) ATTRIBUTE_NORETURN;
+extern void warning (char const *m);
+extern void read_error (void) ATTRIBUTE_NORETURN;
+extern void write_error (void) ATTRIBUTE_NORETURN;
+extern void display_ratio (off_t num, off_t den, FILE *file);
+extern void fprint_off (FILE *, off_t, int);