Porting/Glossary: 'incpath' versus 'incpth'

[jkeenan]

In Porting/Glossary, I observe these two entries right next to each other:

incpath (usrinc.U):
    This variable must precede the normal include path to get the
    right one, as in "$incpath/usr/include" or "$incpath/usr/lib".
    Value can be "" or "/bsd43" on mips.

incpth (libpth.U):
    This variable must precede the normal include path to get the
    right one, as in "$incpath/usr/include" or "$incpath/usr/lib".
    Value can be "" or "/bsd43" on mips.

The body of the entry for incpath is identical to that for incpth, which means that the description for incpath, which twice mentions $incpath, seems internally inconsistent.

Can someone clarify what each of these things is supposed to do -- and whether the wording is accurate or not? (I'm asking because incpth was mentioned in timbunce/devel-nytprof#217.) Thanks.

[Leont]

I have the impression they're actually different things. I think the incpth description is correct but the incpath one isn't. I'm not sure I fully understand incpath but it seems to be some kind of prefix that was only used on BSD 4.3, probably we should just get rid of it to avoid future confusion.

[Tux]

incpth is backported from a patch in Jan 2014. incpath is originated in the original meta/dist repository from a change by Manfredi in November 2010 and never touched by perl-people.

I am aware that this does only add to the confusion. It would require serious digging into the history of the two.