Use Automake's pkginclude feature

[RhysU]

Automake has a magic prefix for the common $(includedir)/$(PACKAGE)
idiom that was in use previously.

[pbauman]

Any idea what version of Automake this went in? I believe you can set a minimum version in AM_INIT so want to make sure we don't need to update.

[RhysU]

http://git.savannah.gnu.org/cgit/automake.git/tree/old/ChangeLog.96 says that feature landed in 1996.

[RhysU]

Or, rather, the tail end of 1995. Either way.

[roystgnr]

I was about to criticize Rhys for giving a revision number rather than a version number, but wait... that's a year number. So automake version is not a worry.

Any advantages to the change other than not having to set includedir?

[RhysU]

None. Just brings it into alignment with common Automake idioms.

[roystgnr]

(either way I'd say this is good to merge, BTW; I just wanted to know if there'd be much payoff for digging through our other similarly organized autotools projects and making the same change)

[pbauman]

Merging.