Test out lclint and its4 on com_err library. One lclint error left on Solaris,

Test out lclint and its4 on com_err library.  One lclint error left on Solaris,
due to deficiencies in lclint.  Its4 chokes in parser.

* com_err.h (struct error_table): Annotate MSGS as pointing to 'shared' data.
(error_message): Returned data is 'observer' and 'dependent'; modifies internal
state.
* com_err.c (default_com_err_proc): Cast various return values to void.
(reset_com_err_hook): Use NULL, not 0.
(com_err_hook): Annotate as 'null'.
* error_table.h (_et_list): Annotate as 'null' and 'dependent'.
(struct et_list): Annotate NEXT as 'dependent' and 'null', and TABLE as
'dependent'.
(struct dynamic_et_list): Duplicate et_list definition, except NEXT is
annotated as 'only' instead of 'dependent'.
(error_table_name, error_table_name_r): Annotate for lclint.
* et_h.awk: Add lclint annotations for initialize_* functions.
* error_message.c (_et_list): Can be 'null'.
(error_message): Explicitly compare against zero.  Cast strerror arg to int.
(et_list_dynamic): New variable, for dynamically allocated list elements;
_et_list is now for statically allocated elements only.
(add_error_table, remove_error_table): Check both lists.
* et_name.c (error_table_name, error_table_name_r): Annotate for lclint.
* init_et.c (et_add_error_table): Change "link" to "e" to avoid confusion with
C library function in analysis tools.
* et1.et, et2.et, t_com_err.c: New files.  Exercise addition and removal of
error tables from list, using both interfaces.
* Makefile.in (LCLINT, LCLINTOPTS, ITS4, ITS4OPTS): New variables.
(do-lclint, do-its4, et1.o, et2.o, t_com_err.o, t_com_err): New targets.  Not
automatically invoked at present.
(FILES): Updated.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@12855 dc483132-0cff-0310-8789-dd5450dbe970