lib/getdef.c: Introduce getlong_normalized

[stoeckmann]

Stay compatible with current configuration files which allow all negative values, but convert them to -1 on the fly.

Print a warning so these values can be modified by an administrator for a future release which won't have this support anymore.

As discussed in #877 (comment)

[alejandro-colomar]

"normalizing" is not something intrinsic to long (what is normal for a long?). I'm not convinced by this function. Rejecting negative values other than -1 is more appropriate to do in functions that handle specific values. I don't like this change very much.

[alejandro-colomar]

A getlong() variant that handles a range (similar to strtoi(3bsd)) is something I have in mind.

Here's what I have in mind:

inline int
getlong(const char *s, long *restrict num, char **endptr, int base, long min, long max)
{
	int  status;

	*num = strtoi(s, endptr, base, min, max, &status);
	if (status != 0) {
		errno = status;
		return -1;
	}

	return 0;
}

inline int
getl(const char *restrict s, long *restrict num)
{
	return getlong(s, num, NULL, 0, LONG_MIN, LONG_MAX);
}

The current getlong() would be (almost) my getl() suggestion, and getlong() would be the argumentful version.

You could call getlong(..., -1, LONG_MAX) for rejecting negative values except -1, and then the caller could report any errors or do whatever is more appropriate.

[alejandro-colomar]

This PR is superseeded by #899.

The commits are:

• e628978
• 953fff2