[krbdev.mit.edu #5562] config file parsing error messages

[Ken Raeburn via RT]

(See also http://mailman.mit.edu/pipermail/kerberos/2007-May/ 
011636.html.)

The error message for "improper format of Kerberos configuration  
file" should include:

* the line number (but watch for CRLF issues on Windows)
* some indication of what the problem is (missing =, [ not at top  
level, bad top-level section syntax, extra }, etc)

Many of the specific parse error types already have distinct error  
codes, but os_init_paths maps several of them onto  
KRB5_CONFIG_BADFORMAT.  (That error code is also used in other places  
for, for example, a required relation not being found, and several  
places in the an_to_ln code.)

There is not currently a way to extract the parse-error line number  
information from the profile library.

Ken