Make sure we don't look before the beginning of the string.

NetBSD Rev 1.5

--- lib/libc/rpc/getnetpath.c.orig	Mon Jan  6 17:10:55 2003
+++ lib/libc/rpc/getnetpath.c	Mon Jan  6 17:17:30 2003
@@ -249,9 +249,9 @@
     /*
      * did find a token, but it might be escaped.
      */
-    if (cp[-1] == '\\') {
+    if ((cp > npp) && (cp[-1] == '\\')) {
         /* if slash was also escaped, carry on, otherwise find next token */
-        if (cp[-2] != '\\') {
+	if ((cp > npp + 1) && (cp[-2] != '\\')) {
 	    /* shift r-o-s  onto the escaped token */
 	    strcpy(&cp[-1], cp);    /* XXX: overlapping string copy */
 	    /*