pkg/57672: pkgsrc guide should mention the iconv const issue

[campbell+netbsd%mumble.net@localhost]

>Number:         57672
>Category:       pkg
>Synopsis:       pkgsrc guide should mention the iconv const issue
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Oct 21 14:25:00 +0000 2023
>Originator:     Taylor R Campbell
>Release:        current
>Organization:
The Const NetBSD *Foundation
>Environment:
>Description:
The iconv const issue -- where different operating systems and standards, and even pages within a single standard, disagree about whether the source buffer pointer is `const char **' or `char **' -- is prevalent enough that we have several dozen patches to address it, and new developers are likely to encounter it in new packages.

The guide should mention the issue and describe what to do.
>How-To-Repeat:
build wip/newsboat as of today
>Fix:
Yes, please!