Add comment about SIZE initialization in xdr.c

sunrpc/xdr.c

@@ -739,6 +739,8 @@ xdr_string (xdrs, cpp, maxsize)
      u_int maxsize;
 {
   char *sp = *cpp;	/* sp is the actual string pointer */
+  /* Initialize to silence the compiler.  It is not really needed because SIZE
+     never actually gets used without being initialized.  */
   u_int size = 0;
   u_int nodesize;