libc: Constify the getcap API

[des]

Summary

MFC after: 1 week
Inspired by: NetBSD

[des]

exp-run requested

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libutil

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getty

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tip

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lpr

[olce]

* (indicating pointers) should preferably be stuck onto the next token without intervening spaces everywhere, e.g.: const char * const *db_array => const char *const *db_array, because in a declaration the presence of the first * delimits the declarator list, which means that what is after the first * is specific to the variable being declared, and not to the next one in the list (that's IMO why that's the common practice for a single *).

Otherwise, looks good.

[kib]

Outer (const char *) const is painful of course, since T** is invariant by T (I think this is the right term).

lib/libc/gen/disklabel.c

71

Is the cast for name needed after your changes?

libexec/getty/subr.c

57

Make dba static as well?

[des]

In D57252#1316026, @olce wrote:

* (indicating pointers) should preferably be stuck onto the next token without intervening spaces everywhere, e.g.: const char * const *db_array => const char *const *db_array, because in a declaration the presence of the first * delimits the declarator list, which means that what is after the first * is specific to the variable being declared, and not to the next one in the list (that's IMO why that's the common practice for a single *).

The style I'm using here is the established style in our code base, see for instance fts(3), nv(9), strerror(3).

[des]

rf