Forgot to add .cxx and .cpp to the second case statement.
Thanks to Daniel Larsson.
diff --git a/Modules/makesetup b/Modules/makesetup
index 47c8dbe..83fdc21 100755
--- a/Modules/makesetup
+++ b/Modules/makesetup
@@ -170,6 +170,8 @@
*.cc) obj=`basename $src .cc`.o; cc='$(CCC)';;
*.c++) obj=`basename $src .c++`.o; cc='$(CCC)';;
*.C) obj=`basename $src .C`.o; cc='$(CCC)';;
+ *.cxx) obj=`basename $src .cxx`.o; cc='$(CCC)';;
+ *.cpp) obj=`basename $src .cpp`.o; cc='$(CCC)';;
*) continue;;
esac
objs="$objs $obj"