5910 libnisdb won't build with modern GCC

*** 18,33 ****
   * information: Portions Copyright [yyyy] [name of copyright owner]
   *
   * CDDL HEADER END
   */
  /*
   * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
- #pragma ident   "%Z%%M% %I%     %E% SMI"
- 
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <ctype.h>
  #include <fcntl.h>
--- 18,32 ----
   * information: Portions Copyright [yyyy] [name of copyright owner]
   *
   * CDDL HEADER END
   */
  /*
+  * Copyright 2015 Gary Mills
   * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <ctype.h>
  #include <fcntl.h>
*** 59,68 ****
--- 58,68 ----
  void *s_malloc(size_t size);
  __nis_mapping_format_t *dup_format_mapping(
          __nis_mapping_format_t *in);
  bool_t dup_mapping_element(__nis_mapping_element_t *in,
          __nis_mapping_element_t *out);
+ bool_t is_string_ok(char *, int);
  
  extern FILE *cons;
  
  /*
   * FUNCTION:    free_parse_structs