Add USES=autoreconf

Differential Revision:	https://reviews.freebsd.org/D792
Reviewed by:	wblock, tijl
Sponsored by:	Absolight


git-svn-id: svn+ssh://svn.freebsd.org/doc/head@45635 c2e8774f-c49f-e111-b436-862b2bbc8956