abuild: fix ldpath handling

it wrongly scanned /lib instead of $datadir/lib, causing bad things to
happen when scanning provides

abuild.in

@@ -1020,7 +1020,7 @@ find_scanelf_paths() {
 	local datadir="$1"
 	local paths="$datadir/lib:$datadir/usr/lib" i= rpaths=
 	if [ -n "$ldpath" ]; then
-		paths="$paths:$(echo "$ldpath" | sed "s|\(^\|:\)|\1$datadir|g")"
+		paths="$paths:$(echo "${datadir}${ldpath}" | sed "s|:|:$datadir|g")"
 	fi
 	# search in all rpaths
 	for rpaths in "$pkgbasedir"/.control.*/.rpaths; do