Added .cxx and .cpp to extensions recognized as source files.

Modules/makesetup

@@ -140,6 +140,8 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 			*.[cC])		srcs="$srcs $arg";;
 			*.cc)		srcs="$srcs $arg";;
 			*.c++)		srcs="$srcs $arg";;
+			*.cxx)		srcs="$srcs $arg";;
+			*.cpp)		srcs="$srcs $arg";;
 			\$*)		libs="$libs $arg"
 					cpps="$cpps $arg";;
 			*.*)		echo 1>&2 "bad word $arg in $line"