Work around .cpp suffix rules.  These rules are not actually needed as the files
are distributed with the tarball.  Upstream workaround of setting SUFFIXES=
earlier in the Makefile only works with GNU make.

Index: src/res/Makefile.am
--- src/res/Makefile.am.orig
+++ src/res/Makefile.am
@@ -38,7 +38,3 @@ libres_a_DEPENDENCIES = $(RES_LIBADD)
 EXTRA_DIST = $(RES_DIST)
 
 
-# This lists the actual makefile rules for each target.
-@RES_TARGETS@
-
-