The install-info command in %preun of autogen is missing a trailing colon; it
ends with "||", should be "|| :".
Which version are you looking at? The install-info in rawhide (5.8.7-5)
certainly has it on.
Looks like you fixed it one day after this bug was filed in 5.8.7-4 (CVS rev 1.6):
Yep. Now to fix gtksourceview-sharp, XaraLX and boo. boo is a bigger pain though :-(