Please consider the following trivial change which allows ppc64le to build xdelta:

[baude@localhost xdelta]$ git diff
diff --git a/xdelta.spec b/xdelta.spec
index 96bf779..101ffe2 100644
--- a/xdelta.spec
+++ b/xdelta.spec
@@ -33,7 +33,7 @@ algorithm to replace the standard diff program used by RCS
 %patch2 -p2 -b .man-page-day
 
 %build
-autoreconf -v
+autoreconf -fiv
 %configure
 make %{?_smp_mflags} V=0