Bug#471193: xserver-xorg-video-sunffb fails to set provides with -j2

["Bernhard R. Link" <brlink@debian.org>]

Package: xserver-xorg-video-sunffb
Version: 1:1.1.0-3

./debian/rules says:

binary-arch: build install serverabi

but serverabi in debian/xsfbs/xsfbs.mk does not depend on install
while install (via dh_clean -k) removes the file
debian/xserver-xorg-video-sunffb.substvars serverabi is appending to,
thus when running with dpkg-buildpackage -j2 the provide (and the other
fields) may get lost.

Solution is either to make serverabi depend on install (perhaps
in a configurable way) or call serverabi not via dependency but by
a sub-$(MAKE).

Hochachtungsvoll,
	Bernhard R. Link